Human Body Systems
A.P. Bio Project
Yuru Zhang, Per. 4
Table of Contents
 Digestive System, Slides 3-13
Reproductive System, Slides 95-107
Circulatory System, Slides 14-26
Nervous System, Slides 108-118
Respiratory System, Slides 27-35
Endocrine System, Slides 119-125
Excretory System, Slides 36-46
Immune System, Slides 47-58
Muscular System, Slides 59-72
Skeletal System, Slides 73-85
Senses System, Slides 86-94
Digestive System
 The function of the digestive system is to
break down food into small molecules our
body can use to build cells, provide energy,
and to dispose of waste products.
Organ Functions
 Mouth: the salivary glands release fluids to form saliva,
which breaks down food & kills germs
 Esophagus: Muscle contractions (peristalsis) channel
food to stomach
 Stomach: stores food that is being broken down with
acid & enzymes
 Small intestine: bile from liver & pancreas enzymes
break down food molecules, absorbs nutrients into
Organ Functions
Pancreas: secretes digestive enzymes (breaks down protein,
fats, carbs), makes insulin, metabolizes sugar
Liver: produces bile, digests fat, breaks down toxins, processes
nutrients from small intestines
Gallbladder: stores & concentrates bile
Large intestine (colon): Processes digestive waste, makes it
easier for waste to be emptied out
 Rectum: connects lg. intestine to anus, sends signals to brain
when waste leaves colon about to exit body
 Anus: sphincter muscles control excretion of liquid, solid, or
gaseous waste
Other parts
 The cecum is the beginning of the ascending lg. intestine,
and it collects all the waste from the sm. intestine.
 The plyoric sphincter allows food to pass from the
stomach to the duodenum of the small intestine.
 The cardiac orifice is a opening past the diaphragm,
which allows the esophagus to communicate with the
 The appendix is the small pouch at the end of the lg.
intestine that has to practical use. It sometimes builds up
waste, which can lead to a painful swelling, a.k.a.
Accessory organs make the digestive
chemicals (enzymes, saliva, bile) that
digest, break down food
Alimentary organs absorb nutrients from
the digested food, and they form the
digestive tract.
Digestion & Role of
 Large molecules have to be digested, since small
intestines can only absorb small molecules with facilitated
diffusion or active transport. Large molecules won’t fit.
 Some compounds have to be broken down, then
reassembled in order for our digestive system to digest
 Enzymes are used to break down food, toxins, and many
other compounds involved in digestion.
Phys. vs. Chem. Digestion
 Physical digestion, like the name, involves the mechanical
breaking-down of food. The teeth are extremely useful in
grinding up food into smaller particles. Also, the stomach
churns the food up, which effectively smashes and
condenses the food pieces up together.
 Chemical digestion involves saliva, digestive enzymes,
stomach acid, and bile. They all break down food into
smaller molecules through chemical processes, such as
Carb & Protein digestion
Carbohydrates are hydrolyzed in the stomach and
upper small intestine to form monosaccharides, which
can be absorbed by the small intestine.
 Carbohydrates are digested by salivary amylase,
maltase, sucrase, and lactase.
 Proteins are mainly digested by enzymes. These
include proteases, pepsin, trypsin, etc. Amount of
protein, concentration of acid are factors to how the
proteins are broken down.
 Proteins are digested in the stomach and upper small
Acute pancreatitis, which is a inflammation of the pancreas.
Symptoms include chills, abdominal pain, weakness, & weight
loss. More common in men than women. It’s caused by
enzymes that digest pancreas tissue, causing the pancreas to
bleed and swell up. Cause could be genetic, alcoholism, or
unknown. It can be treated with ERCP or by simply avoiding
alcohol and fats. Also, painkillers may help ease the symptoms.
Crohn’s disease is an inflammation of the digestive system,
from the mouth to the anus. Abdominal pain and diarrhea are
common symptoms. It occurs in both sexes and runs in
families. It usually begins in young people between 13 to 30
years of age. Smoking may increase risk of disease. People of
Jewish ancestry also have a higher risk. It can be treated with
surgery and/or antibiotics.
Digestive System Sources
 A.P. Bio textbook
Circulatory System
The purpose of the circulatory system is to
transport blood, oxygen, and carbon dioxide
to and from the lungs. Also, the system
transports nutrients to cells and waste away.
Oxygen goes from the lungs to the cells and
travels through the bloodstream throughout
the body. Carbon dioxide travels to the lungs
to be released.
Structure & Functions
Arteries, blood vessels that transport blood from the heart
throughout the body. It’s made up of elastic fibers and
connective tissue to make it able to withstand the pressure of
blood flow.
Veins, blood vessels that carry deoxygenated blood back to the
heart, except pulmonary vein, which carries oxygenated blood
to the heart. They have valves that prevent blood from flowing
back. They are located nearer to the skin and are more visible
than arteries. Veins have a structure much like arteries, allowing
them to transfer large volumes of blood, without bursting.
Capillaries, small blood vessels that form a bed winding
throughout muscle. This structure allows them to move
substances, such as oxygen and carbon dioxide in and out.
Also, their small size enables them to quickly and efficiently
transport erythrocytes to various sites in the body.
Blood Routes in Heart
 Blood enters the heart from the vena cava, which
transfers deoxygenated blood to the right atrium. Then,
the atrium pumps the blood into the right ventricle (past
the AV valve), up through the pulmonary artery (past the
semilunar valve) to the lungs. The blood is oxygenated
there, and then, the blood reenters the heart from the
pulmonary vein. The blood is now in the left atrium,
which pumps it through the AV valve into the left
ventricle. From there, the blood goes past the semilunar
valve up into the aorta, which pumps blood throughout
the body. Both valves depend on the pressure of the
arteries and veins. When the arteries have more pressure
than the veins, the AV valves open and the semilunar
valves close. When the veins have more pressure, the AV
valves are shut and the semilunar valves open.
Composition of Blood
 Plasma, a great portion of blood, liquid, mostly water. It
contains nutrients like glucose and fatty acids that are
transported throughout the body. Also, it removes waste
products, like urea and carbon dioxide. Plasma is useful
for blood-clotting, carrying antibodies, proteins, and
 Erythrocytes, red blood cells, delivers oxygen throughout
the body using the blood flow and the circulatory system.
It’s reddish color is from the large amounts of iron in the
hemoglobin (oxygen binds to this molecule).
Leukocytes & Platelets
• consist of lymphocytes and monocytes
• B lymphocytes, make antibodies
• T lymphocytes, use macrophages, kill virus-infected cells,
help production of antibodies
• Monocytes, become macrophages that “eat” antigens and
dead cells
• Sticky substances that help clot bloods to prevent excessive
• Forms with exposure to air, forms clot, dries and hardens
to a scab
diffusion in
Small and a
Able to squeeze
through tight
Open and Closed Systems
Closed Circulatory
• Mostly vertebrates and a few invertebrates
• Blood is only in the blood vessels, doesn’t go to body
• Humans have a closed circulatory system.
Open Circulatory
Arthropods and mollusks
Blood doesn’t travel with blood vessels
Fills body cavities
Surrounds tissues with blood, diffuses cell to cell through
the circulatory system
• Crayfish are an example.
Circulation Variations
Gills, ventilation,
current of water
flowing over the
respiratory surface
exchange, allows
oxygen to be
transferred to the
Positive pressure
breathing, oral cavity
rising forces air down
Elastic recoil of lungs
forces air out of lungs
Negative pressure breathing,
air is pulled into the lungs,
diaphragm contracts to
increase lung volume
Surface tension
allows movement of
lungs to also move
the rib cage.
Birds use parabronchi to
exchange gases, one direction air
flow, no alveoli. More complex
ventilation. Birds can breathe
better at higher altitudes.
Circulation Variations
Three-chambered heart, similar to amphibians.
Two atria, ventricles are undivided (mixing of
deoxygenated and oxygenated blood may
Circulations is divided into
three channels: pulmonary
trunk, right and left
systemic trunks
Atherosclerosis is a disease of the arteries that can lead to
heart attack, stroke, and death.
 Occurs when plaque hardens, blocking arteries (blood flow is
People with high bad cholesterol levels and high blood
pressure are at risk (unhealthy diets, lack of physical activity
also up the risk)
Symptoms: sudden weakness, dizziness, breathing problems,
trouble hearing or seeing
Treatment: medication to decrease plaque buildup, can prevent
blood-clotting, medical procedures done on blocked arteries,
healthy lifestyle habits can prevent this disease
Raynaud’s Disease
 Raynaud’s disease is a disorder of the arteries.
Causes blood vessels to narrow, reducing blood flow
Cause: unknown (other diseases and conditions can be
triggers), cold temperatures and stress are also triggers
Symptoms: Affected body part will turn white and blue, skin
will tingle and burn
Five percent of people in U.S. have this disease.
Treatment: no cure, medicine and/or surgery may temporarily
relieve symptoms, easily prevented by avoiding triggers
Circulatory System Sources
AP Bio book, pgs. 884-889
Respiratory System
 The function of the respiratory system is to supply
oxygen to the blood and to expel carbon dioxide from the
 It does this by breathing in air (inhaling oxygen, exhaling
carbon dioxide).
Alveoli Features
 They are the body’s primary gas exchange units.
 Located in the lungs.
 Shaped like interlinking sacs
 Thin, fluid-lined walls allow gases to dissolve
 Capillaries surround them, so oxygen can enter
bloodstream (diffusion)
 Large surface area, smaller volume
Transport of Carbon Dioxide & Oxygen
 Carbon dioxide is transported by red blood cells.
 Carbon dioxide is dissolved in the plasma (bound to the
 Oxygen is also bound to the hemoglobin (at a different
site) and is carried around by the red blood cells.
Path of Oxygen
 Enters mouth and/or nose.
 Passes through trachea (windpipe)
 Enters bronchi, then to bronchioles
 Reaches alveoli, where the oxygen is in close contact with
the bloodstream.
 Diffuses across and is bound to the hemoglobin in RBC’s
 Oxygen reaches the heart and spreads throughout body
with circulatory system.
Inhalation & Exhalation
• Diaphragm
• Intrapleural
space expands
• Pressure
decreases, lung
• Air flows in
Rises up
Pressure on
lungs increases
Lung volume
Air is expelled
Chronic Obstructive
Pulmonary Disease
Lung disease that makes it hard to breathe
Symptoms: cough, fatigue, respiratory infection, wheezing,
shortness of breath
Causes: smoking, gaseous fumes, secondhand smoke,
Prevalence: third leading cause of deaths in U.S., more females
than males, around 16 million people in U.S. with COPD
Treatments: quitting smoking, inhaler usage, anti-inflammatory
medicine, antibiotics, avoiding cold air and smoking, stay away
from air pollution sources, surgery
It’s an infection of the lung, and affects breathing.
Causes: bacteria and viruses that infect the nose or mouth spread
to the lungs, direct infection of lungs, or inhalation of foreign
substances into the lungs
Smoking, Cerebral palsy, lung disease, immune system problems
are just some of the factors that increase the risk of getting
Symptoms: cough, fever, chills, shortness of breath, headache,
3 million pneumonia patients each year, 60,000 die, 1/3 of them
are over 65 years old, 4% of children in U.S. are infected
 Treatments: antibiotics, breathing treatments, drinking plenty of
fluids, breathing in warm air
Respiratory System Sources
 A.P. BIO Book
The functions of the excretory system are:
Remove solid and liquid waste from body
 Excretes cell by-products
 Maintains balanced chemical concentrations
 Ammonia
Common in aquatic species
Readily diffuses from organism’s membranes to
surrounding water
Needs to be diluted down by large sources of water
High concentrations are toxic to organisms
Lost as ammonium ions by most fish
Soluble in water
 Urea
Secreted by mammals, sharks, amphibians, bony fishes
Produced in liver, combining ammonia with carbon
Low toxicity, requires much less water, less loss of water
Useful for organisms living w/o access to sufficient water
Requires energy to produce (amphibians could switch
between excreting ammonia and urea depending on water
Soluble in water
 Uric acid
Reptiles, birds, and insects secrete this
Not as toxic as ammonia
Insoluble in water
Excreted as a paste
Little water loss, good for organisms w/o much access to
Takes up a lot of energy to produce this waste
The functions of the nephron are to remove waste and excess
substances from the blood and to replenish the body’s sodium,
potassium, and phosphorus levels.
Nephron Processes
• Body fluid is forced through selectively
permeable membranes
• water, salt and nitrogenous wastes are
sent to excretory system (filtrate)
Selective reabsorption
• Active transport reabsorbs substances
like glucose, salts, and amino acids from
• Toxins and excess salts are left in filtrate
Nephron Processes
• Using active transport, toxins and waste are
added to filtrate from body fluids
• Water, with osmosis, is pushed to the excretion
• Filtrate leaves system and body
• In humans, urine is excreted (produced by
• Blood vessels around nephrons are useful in
transportation of fluids
Interstitial nephritis
 Kidney disease, inflammation of tubule spaces
 Symptoms: urine in blood, fever, nausea, vomiting,
weight gain
 Causes: long-term use of medications like Tylenol and
aspirin, too much potassium in blood, too much uric acid
and calcium
 Over 39,480 nephritis deaths in U.S. each year
 Treatment: Less salt and protein in diet, antiinflammatory medication
Bacterial infection of the bladder
Causes: bacteria that enter from the urethra, may spread to
kidneys, diabetes, bladder blockage, or pregnancy can increase
risk of cystitis
Symptoms: cloudy and bloody urine, pain with urination, urge
to urinate often even with an empty bladder
Prevalence: more women than men, most deaths occurred in
Mexico and Brazil, usually not deadly, 15 deaths in U.S.
Treatment: antibiotics, drinking plenty of water, medication
that reduces pain and urination urge
Excretory System Sources
AP Bio Book, Chapter 44
Immune System
 Protects body from infection
 Ingest and destroy pathogens
 Detects viruses, parasites, etc. and can tell difference
between unhealthy and healthy tissue.
Major Organs
Adenoid, located in back of nasal cavity above roof of mouth,
spongy tissue helps protect against infection
Tonsils, located on sides of throat, helps fight infections,
tonsils may get infected (tonsillitis)
Lymph nodes, oval-shaped organs located in various places in
body, trap foreign particles, become inflamed or enlarged
during infection or cancer
Spleen, filters blood, kills infected RBC’s, initiates immune
response if foreign particles are found in blood
Lymphatic vessels, carry lymph throughout body, foreign
particles are accumulated, so macrophages, dendritic cells, and
lymphocytes can kill the germs
Recognition of Pathogens
 Lymphocytes recognize foreign particles specifically and
causes a immune response.
 Antigens are foreign proteins or polysaccharides that
cause lymphocytes to respond.
 Antibodies bond to foreign particles to prevent them
from entering and damaging cells. They can also trigger
immune responses to destroy the foreign particles.
Innate & Acquired Immunity
Not antigen-specific • Lymphocytes
Skin and mucus are • Cells from
red bone
physical barriers
• Sweat, tears, and
• Cells are
saliva break down
found in
blood and
• Neutrophils and
macrophages use
• Immunity that
develops through
exposure to
• Antibodies, T and
B cells
• Can cause allergic
• Cells might mature
at thymus
Active & Passive Immunity
• antigen-containing
substance injected
• Immune response
is stimulated
• antibodies build up
• Vaccines
• Body encounters live
• Immune system
remembers it
• Body will react faster to
counter the pathogen the
next time
• Immunity can be
passed on from
• antibodies are
transferred from
• Immunity is not
developed; it’s
already there or given
Humoral & Cell-mediated
• Deals with potential infectious
• Both store
particles in tissue and blood
• Uses antibodies
info into
• Macrophages ingest and
destroy infectious agents
• Both are
• Helper-T cells recognize
types of
infectious agent components,
cause immune response
• B-Cell Activation
• Deals with infected
• Killer-T cells destroy
infected cells
• Antigen and foreign
particle info are
stored in memory
• Helper T-Cells
• Secondary response
• Antigens, cytokines from
helper T’s activate B cells
• Activated cells can be
memory B cells or
antibody-secreting plasma
• Degrade bacteria and cause
exponential activation of
other B cells
• Activated by binding
to surface proteins on
infected cell
• Cytokines from helper
T cells help activation
• Activated T cells kill
infected cells by
secreting proteins on
T Lymphocytes
B Lymphocytes
B & T Lymphocytes
 Antibiotics help kill bacteria by destroying their cell wall,
by recognizing and disabling certain chemicals and
enzymes that are unique to the bacteria. They may
prevent the bacteria from reproducing.
 Viruses are unaffected by antibiotics, because they only
contain a piece of DNA or RNA. Viruses can only
reproduce and gather nutrients using their host cells, so
they don’t have a metabolism to disrupt with antibiotics.
Human immunodeficiency virus, a retrovirus, attacks the
body’s immune system, preventing the body from effectively
fighting infections.
Symptoms: No early symptoms, possible headache, fever,
enlarged nymph nodes, later on: pneumonia, brain infections,
widespread diseases and fungal infections
Prevalence: About 40 million people in the world have this
disease, 25 million have died, 85% transmitted through
heterosexual intercourse, homosexual transmission and
intravenous drugs are a large proportion of AIDS diagnosis
causes in the U.S.
Treatment: medications like Raltegravir, reverse transcriptase
inhibiting drugs (zidovudine), antiretroviral drugs and therapy
Systemic lupus
erythematosus (SLE)
An autoimmune disease (immune system attacks healthy
tissue), exact causes not known, possibly caused by certain
drugs. Can affect almost any body part.
Symptoms(depends on part of body affected): Fatigue, fever,
hair loss, sunlight sensitivity, skin rashes, coughing up blood
Prevalence: Occurs more frequently in women than men, more
African Americans and Asians than other races, people > 10, <
Treatment: no cure, symptoms can be controlled with
NSAIDs, skin creams, or corticosteroids (or any other relieving
drug that treats the affected body area), regular screening,
immunization, and appointments are recommended
Immune System Sources
 AP Bio Book, Chapter 43
Muscular System
 Allows body to move around, locomotion (skeletal
 Ability to generate heat
 Movement by contraction and relaxation of muscles
 Cardiac muscle in heart pumps blood
 Smooth muscle in organs, lines digestive tract (helps in
Muscle Types
Skeletal Muscle
 Striated muscle, myofilaments create light and dark band
 Attached to bones, movement of body
 Contains repeating units, sarcomeres
 Bundle of muscle fibers
 Muscle fibers, bundle of myofibrils
Cardiac Muscle
 Striated muscle, like skeletal
 Different electrical and membrane properties
 Ion channels in cell plasma membrane
 Action potential triggered without immune system
 Intercalated disks, where the cells interlock
 Gap junctions, electric coupling between the cells
 Action potential is spread to all the cells, heart contracts
Smooth Muscle
 Makes up hollow organs, (blood vessels, GI tract,
bladder, & uterus)
 Smooth, no cross striations
 Smaller in diameter than skeletal muscle fibers
 Single-unit muscle in dense sheets/bands
 Multi-unit muscle have no interconnecting bridges, mixed
with connective tissue fibers
Sliding-Filament Model
 Thin filaments and thick filaments don’t change length
during sarcomere shortening
 Filaments slide past each other longitudinally
 Thin and thick filaments overlap
 I band and H zone shrink (Less thin or thick filament
only areas)
 Myosin and actin interactions
 Neurotransmitter biochemicals
 Carry nerve impulses across synapses (between neurons)
 Carries impulses to muscle cells through motor plate
 Generates muscle contractions.
 Vital to nervous system and muscular system
 Chemical messenger
 Important role in memory
Calcium ions and Cross-bridges
Muscle fibers only contract with motor neuron stimulation
Binding sites blocked by tropomyosin regulatory protein
Calcium ions bing to regulatory proteins forming troponin complex
Exposes myosin binding sites on thin filament
Muscles contract and relax, depending on concentration of calcium
ions in cytosol
Cross-bridges form when myosin heads bind to actin, broken when
new ATP molecule binds to myosin head
ATP is hydrolyzed to ADP, cross-bridge releases ADP and inorganic
phosphate, thin filament slides
Actin and Myosin
Make up thin
Long tail region and
globular head region
(tails adhere to tails)
Binds to myosin
head to form a
Make up thick
Helps in hydrolysis
of ATP
Myosin head is center
of bioenergetic
reactions (binding of
ATP, hydrolysis of
Duchenne muscular
Inherited disorder involving the weakening of the muscles
Rapidly-worsening version of muscular dystrophy
Symptoms: fatigue, mental retardation, muscle weakness,
difficulty walking
Causes: Inherited, defective gene for dystrophin
Prevalence: More common in males than females, 1 out of
3600 male infants
Treatment: No cure, future gene therapy, physical activity (a
body in motion will stay in motion), orthopedic appliances
 Inflammation of a tendon from minor impact on an affected
area, can occur at any tendon site
 Symptoms: Pain and loss of motion at site of tendon and
surrounding area
 Causes: everyday activities (gardening, shoveling, sports, etc.),
incorrect posture, medication reactions, stress from arthritis
or gout
 Prevalence: More common in older adults (over 40)
 Treatment: Rest, icing the area, anti-inflammatory
medication, for more serious tendinitis: steroids, physical
therapy, surgery
Muscular System Sources
 A.P. Bio Book, Chapter 49
Skeletal System
 Structural support
 Protection of vital organs
 Allows for movements, with muscles
 Stores minerals like calcium and phosphorus
 Produces red blood cells and white blood cells
 Can store lipids
Movement: Bones
 Muscles have to contract against bones of some type of
 Hydrostatic, exoskeleton, endoskeleton
 Joints allow for movement flexibility (endoskeleton)
 Peristalsis, rhythmic waves of muscle contractions
Movement: Ligaments
 Provide joint stability in movement
 Prevent hyper-extension or hyper-flexion
 Bind bones to other bones and joints
 Elastic, able to lengthen under tension
Movement: Muscles
 Contract against bones to move
 Able to convert chemical energy into kinetic energy
 Myofibrils are part of the contraction process
 Sliding Filament Model
Movement: Tendons
 Connect muscles to bones
 Able to withstand tension
 Similar to ligaments
 Work together with muscles to create movement
 More elastic than ligaments
 Able to function as springs, provide stability during rest
Hydrostatic skeleton
 Main skeleton type in cnidarians, flatworms, nematodes,
& annelids
 Fluid-filled compartments under pressure
 Movement through the changing of the shape of the
 Peristalsis, rhythmic waves of muscle contractions
 Cushion internal organs, provide support for terrestrial
movement (crawling and burrowing)
 Hard outer-covering on surface of animals
 Shell enlarges as animal grows (outer edge growth)
 Molluscs, bivalves, arthropods
 Jointed exoskeleton --- cuticle, non-living coat secreted by
epidermis (arthropods)
 Cuticle is made of chitin
Protein matrix combines strength with flexibility
Molluscs have a mantle, sheet-like body wall extension
 Bivalves have hinged shell (muscles attached inside close
Support elements, like bones, are buried in soft tissues of body
 Echinoderms
 Ossicles (hard plates beneath skin)
Made of calcium carbonate and magnesium carbonate
Bound together by protein fibers
Cartilage and bone combination
Axial (skull, backbone, rib cage)
Appendicular (limbs and pelvic girdles)
Bones fused together with ligaments, joints provide flexibility
Long Bone
Thinning of bone tissue, bones lose density (occurs over time)
Most common bone disease
Affects about 20% of all American women over 50
Causes: estrogen drop in women, testosterone drop in men,
chronic arthritis, eating disorders, Vitamin D deficiency
Symptoms: Bone fractures, pain or tenderness, stooped posture
Treatment: Bisphosphonates, Calcitonin, Raloxifene
High calcium diets and moderate exercise can prevent
 Inflammation of joints, cartilage breakdown
 Causes: autoimmune disease, broken bones, infections, “wear and
 Occurs in both men and women, affects one of five people in U.S.
 Symptoms: joint pain, swelling, reduced movement of joint, stiffness
 Treatment: Lifestyle changes (exercise, physical therapy, diet change),
medication: biologics, corticosteroids, immunosuppressants, surgery
(joint rebuilding or replacement)
Skeletal System Sources
A.P. Bio book, Chapter 49.5
Senses System
 Receive signals of physical deformation from stimuli like
pressure, touch, stretch, motion, and sound
 Sense any type of mechanical energy
 Mammals require mechanoreceptors to have the sense of
 Embedded in connective tissue, location depends on best
stimulus (can be deep in skin or on the surface)
 Respond to heat or cold to regulate body temperature
 Send signals to body surface and core temperatures
 Send info to posterior hypothalamus
 Receptors might be encapsulated, branched dendrites or
naked dendrites of sensory neurons
 General receptors (transmit info about solute
concentrations in solution)
 Osmoreceptors (mammalian brain)
Water receptors (feet of houseflies)
 Specific receptors (transmit info to certain kinds of
Receptors for specific molecules
Chemoreceptors in male silkworm moth antennae (detect
female moth sex pheromones)
 Electromagnetic receptors that detect visible light
 Often located in the eyes
Proteins absorb photons, cell membrane potential is
 Photoreceptor cells: rods and cones, photosensitive
ganglion cells
 Rods are sensitive at low light levels, colors cannot be
 Cones are only sensitive to higher light levels (more
Pain receptors
 Also known as nociceptors
 Class of naked dendrites located in the epidermis
 Stimulus leads to defensive reactions
 Different receptors respond to different stimuli (excess
heat, pressure, or certain chemicals from damaged or
inflamed tissues
 Histamines and acids are some chemicals that trigger
 A visual pigment, made up of light absorbing retinal
bonded to an opsin protein
 The sensitivity of rod cells (light detection cells in eyes) is
dependent on Rhodopsin
 Comes from b-carotene (carrots)
 Bright light causes Rhodopsin to change shape,
Cell Signaling
Signal transduction pathway, signal on cell’s surface is turned into a cellular
Cell detects signal molecule from outside
Detection results in molecule binding to a receptor protein located on cell surface or
Receptor protein is changed during binding
May require a series of steps and different molecules (signal transduction pathway)
Transduced signal triggers cellular response
Any imaginable cellular activity (catalysis, cytoskeleton rearrangement, gene activation)
Senses System Sources
 A.P. Bio Book, Chapters 11 and 49
Reproductive System &
 The function of the
system is to ensure the
survival of a species
through the
procreation of
 Spermatogenesis --the production of
mature sperm cells
Sexual vs. Asexual
Haploid gametes are fused
Zygote is formed
Meiosis occurs
Genetic variability is
• Greater reproductive
success when environment
changes quickly
• All genes come
from one parent
• Fission
• Budding
• Fragmentation and
• Common in
• Relies on mitotic
cell division
Oogenesis is the
development of
mature ova or eggs.
Cytokinesis is
unequal. Of the four
gametes produced,
one is a large
daughter cell, which
is able to become the
ovum. The other
three are smaller
cells, polar bodies
that eventually
Menstrual vs. Estrous Cycle
• Humans, other primates
• Endometrium is shed •
from uterus through
cervix and vagina
• Behavior changes are
not as pronounced
• Receptive to sexual
activity throughout
• Mammals other than
Ovulation occurs when
• Endometrium is
endometrium has
reabsorbed by the
thickened and a rich blood
supply has been
• Change in behaviors
during cycles
• Estrus or heat is the
only time mating can
Hormonal Control
 Principal male sex hormones are androgens
 Testosterone
 Produced by Leydig cells in testes, located near the
seminiferous tubules
 Male reproductive system is directly affected by the
 Primary (development of vasa deferentia) and secondary
(voice deepening, facial and pubic hair) sex characteristics
Feedback Mechanism
 Negative feedback on the hypothalamus and anterior
pituitary regulates blood levels of luteinizing hormones,
follicle-stimulating hormones, and gonadotropin-releasing
 Leydig cells produce testosterone & other androgens,
that stimulate sperm production and affect the primary
and secondary sex characteristics
 Each hormone acts only on cells with the specific
receptors for it
After completion of fertilization, the cell divides rapidly
Cells undergo DNA synthesis and mitosis phases of cell cycle,
skipping G1 and G2 (little or no protein synthesis)
Zygote is split into small cells called blastomeres
First divisions form cluster of cells known as morula
Fluid-filled cavity (blastocoel) forms within morula
Blastula (hollow ball of cells surrounding large blastocoel)
Animals other than mammals have polar eggs and zygotes
Cleavage of eggs in frogs and other animals depends on the
distribution of yolk in the egg
Morphogenetic process that rearranges blastula cells to form a three-layered
embryo (gastrula)
Same general mechanisms in all species: changes in cell motility, cell shape, and
cellular adhesion to other cells/molecules
Embryonic germ layers: ectoderm (outer layer), endoderm (inner layer lining the
digestive tract), and mesoderm (fills space between ectoderm and endoderm)
Ectoderm develops into: epidermis, sensory receptors, cornea and lens of eye,
nervous system, tooth enamel, epithelial linings mouth and anus, etc.
Mesoderm develops into: notochord, skeletal system, muscular system, excretory
system, circulatory system, reproductive system, lining of body cavity, adrenal
cortex, etc.
Endoderm develops into: epithelial linings of digestive tract and respiratory
system, lining on urethra, bladder, and reproductive system, liver, pancreas, thymus,
Germ Layers
Process in which three embryonic germ layers develop into organs
Notochord is formed from dorsal mesoderm (unique in vertebrate
Neural crest is a band of cells that develop along the border where
the neural tube pinches off from the ectoderm. Neural crest
forms teeth, skull bones, etc. (fourth germ layer)
Morphogenesis and cell differentiation refine the organs produced
from the germ layers
Somites, serially arranged on the notochord
Dissociate into wandering cells that migrate to new locations
Form muscles associated with axial skeleton
Infertility is the inability to conceive and produce offspring
Causes: Physical and emotional factors
Female: autoimmune disorders, cancer, diabetes, eating
disorders, older age, obesity, thyroid disease
Male: pollutants, impotence, infection, birth defects, smoking,
older age, STD’s, injury, surgery
Three to seven percent of all couples worldwide are affected
by infertility
Symptoms: Inability to become pregnant, may cause painful
Treatment: education/counseling, fertility treatments,
medicines treating infections and clotting disorders
Cervical cancer
Cancer beginning in the cervix (lower uterus)
Starts as dysplasia, takes years for the cancer to develop
Third most common type of cancer in women
Causes: Develops slowly, HPV (virus spread through sexual
intercourse), weakened immune system
Symptoms: abnormal vaginal bleeding, longer and heavier
periods, back pain, bone pain, fatigue, loss of appetite, pelvic
pain, weight loss
Treatment: depends on stage, size and shape of tumor, and
woman’s age and health, hysterectomy (removal of uterus),
radiation, chemotherapy
Reproductive System Sources
 A.P. Bio book, Chapters 46 and 47
Nervous System
 The function of the nervous system is to send signals
between cells.
 The nervous system controls and regulates movement and
 The humans nervous system controls all mental activity,
including thoughts, learning, and memory
 Central Nervous System: small brain, longitudinal nerve
cords in simple invertebrates (flatworms)
 CNS in vertebrates consists of the brain and spinal cord
 Complex invertebrates and arthropods have more
complicated brains and ventral nerve cords with ganglia
(clusters of neurons)
 Peripheral Nervous System: nerves that connect the CNS
with the rest of the body
 PNS in vertebrates consists of nerves and ganglia
Reflex arc
The right cerebral
hemisphere deals with
estimation and
approximation calculation,
contextual and
intonation/accentuation in
The diencephalon regulates
the activities of the
autonomic nervous system
and controls internal organ
Uses the cranial nerves to provide motor
and sensory function to face and neck;
also regulates cardiac and respiratory
function and CNS (maintains
consciousness, regulates sleep cycle)
The left hemisphere deals
with exact calculation and
direct fact retrieval,
grammar/vocab and literal
Responsible for
finite motor activity
movement) and
supervised learning
Nerve Impulse
Electric current travels across neurons (dendrites or axons)
Ions move through voltage-gated channels that open and close in response to
an electrical voltage.
Sodium-potassium pumps push sodium out of cell, bringing potassium in.
Cell exterior is positively charged while interior is negatively charged.
Membrane potential is created.
Stimuli cause the plasma membrane of a dendrite to open sodium channels,
and the sodium ions flow into the cell (action potential)
Now the interior is positively charged, while the exterior is negatively charged
(depolarization). Membrane is repolarized when the potassium ions flow
Neurons communicate with electrical synapses (contain gap junction
allowing electrical flow between cells) and chemical synapses
Chemical synapses release neurotransmitters, packing it into synaptic
Neurotransmitters are released by exocytosis when the terminal membrane
is depolarized, and the voltage-gated calcium channels are opened.
EPSPs are excitatory postsynaptic potentials, where the depolarization of
the postsynaptic membrane bring the membrane potential toward the
threshold (the limit of most depolarizations)
IPSPs are inhibitory postsynaptic potentials (hyperpolarizations produced
when the potassium ion channels are opened) that move membrane
potential away from the threshold.
Direct Synaptic Transmission
 A severe mental disturbance affecting around 1% of the
worldwide population.
 Causes: Unknown, may be affected by genetics, may also
be affected by unknown environmental factors
 Symptoms: Patient is unable to distinguish reality,
hallucination, delusions, lack of emotion, difficulty
sleeping, social isolation, anxiety, childlike behavior,
attention problems, little or no response to other people
 Treatment: antipsychotic medication, supportive
therapies and programs
Parkinson’s Disease
A disorder affecting motor function that inflicts about one
million people in the U.S. Affects 1% of people at age 65, 5%
at age 85
Cause: The destruction of dopamine-producing nerve cells,
leading to loss of muscle function (brain cannot send proper
Symptoms: Blinking, drooling, difficulty swallowing, muscle
aches, slowed movement, difficulty performing fine hand
movements like writing, tremors, stooped position
Treatment: No cure, Levodopa, Mirapex, Eldepryl are some
drugs that reduce the symptoms; deep brain stimulation and
surgery may be other symptom-easing options
Nervous System Sources
 A.P. Bio book, Chapter 48 on Nervous Systems
Endocrine System
 The Endocrine System in charge of secreting chemicals
that control the body’s metabolism.
 The Endocrine System produces hormones to influence
tissue function, growth and development, metabolism,
and reproductive function.
 The main glands are the hypothalamus, thyroid gland,
adrenal gland, pancreas, and the ovaries in females and
testes in males.
 The Endocrine System regulates the body’s temperature,
pH, oxygen levels, and body systems, so the cells are at
optimum performance.
 The thyroid gland is important in homeostatic functions.
Hormones made in the thyroid gland maintain normal
blood pressure, heart rate, muscle tone, digestion, and
reproductive functions
 Feedback mechanisms have an important role in
Feedback Mechanisms
 Negative feedback
Process where the body reacts to reduce and eventually
cease the stimulus
Sweating when your temperature increases
 Positive feedback
Process in which the stimulus is strengthened, increasing
the response
Ex: The mammary glands will continue to secrete milk as
the baby suckles, and the pathway regulating the milk will
continue to be stimulated
Diabetes I vs. II
Diabetes I
• Body’s own immune system
kills pancreas cells that
produce insulin
• Cause: unknown, possibly
autoimmune disorder
• Symptoms: Thirst, hunger,
flushed face, stomach pain,
headache, sweating,
• Treatment: Daily insulin
injections, diet and exercise,
blood sugar monitoring
with glucometer
Diabetes II
• Most common type of Diabetes
• Develops over time
8.3% of the • Causes: Body is unable to make
proper use of insulin, Family
history/genes, poor diet, excess
body weight
Diabetes • Symptoms: Fatigue, hunger, thirst,
increased urination, blurred vision
• Treatment: Exercise, diet, glucose
monitoring, blood sugar
management, weight control, some
blood sugar regulating medications
Thyroid cancer
A cancer that begins in the thyroid gland. Occurs in all age
Causes: radiation therapy, family history, thyroid gland
enlargement (goiter)
Symptoms: Cough, difficulty swallowing, hoarseness, neck
swelling, thyroid lump
Treatment: Surgery (thyroid gland removal), radiation therapy and
radioactive iodine, chemotherapy, thyroid hormone doses to make
up for the gland removal
One out of 97 (1.03%) men and women will get this disease.
Endocrine System Sources
 A.P. Bio Book Chapter 45

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