Transcript The Human Body

Ch 40- Intro. to Animal Structure/Function
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Tissues = group of cells with common structure & function
1) Epithelial - tightly packed, protective covering,
skin, around organs
classify by # of layers: simple vs. stratified (and
pseudostratified) or by shape: cuboidal, columnar,
squamous (flat)
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2) Connective- supports tissues, usually in a matrix
ex. blood, bone, cartilage, adipose (fat)
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3) Nervous - sense stimuli and transmit signals
neuron - functional part that carries signals
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4) Muscle - long protein fibers, aids movement & support
ex. skeletal, striated, cardiac, smooth
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• Organ - groups of tissues, work
same function
together for
• Mesenteries – connective tissue between cavities
• Organ system - groups of organs working
together
• Organism - group of organ systems working
together
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• animals must maintain a stable environment
• involves regulating fluid, temp, gas, pH etc.
• uses negative feedback = sensing
mechanism (receptor) detects changes &
activates a second mechanism (effector) to
reverse problem
• A buildup causes a shut down and vise versa
• Positive feedback = triggers amplification
instead, ex. Childbirth
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Ch 41
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• homeostasis is also important in nutrition,
balance fuel needs
• chemicals such as leptin help regulate appetite
• glucose sugar levels are kept in check by the insulin
produced in the pancreas
• glucagon is released when blood sugar is low,
glucose is released
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• essential nutrients that must be obtained
from the diet: vitamins, minerals, water,
carbon and energy
• 8 A.A. that need to be ingested (body
can’t make)
• Same with some fatty acids
• Vitamins – organic molecules needed in
ones diet, p.877
• Minerals – inorganic molecules needed in
smaller amounts, p.878
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• 4 parts: ingestion (eating), digestion
(break down), absorption (get nutrients)
and elimination (feces)
• Digestion can be intracellular by
vacuoles and enzymes (Paramecium) or
extracellular by some breakdown outside
of the cells, usually starts in a cavity
(gastrovascular/alimentary canals)
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1) Mouth – mechanical breakdown by teeth,
chemical breakdown by amylase (salivary
glands) = enzyme breaks down starch
• food gets formed into a ball or bolus
2) Pharynx – food moves down this tube also
called the throat
• flap of tissue called epiglottis, keeps food
down correct track
3) Esophagus – tube that leads to the stomach,
food moves by muscle contractions called
peristalsis
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4) Stomach – elastic muscle, churns food,
holds 2L, gastric juices (HCl), pepsin
released to break down proteins, now
called chyme
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5) Small intestine – pyloric sphincter opens, food passes
•6m segmented tube, first part is the duodenum, here
enzymes are released from the walls:
•proteases break down proteins
•phosphates that break down nucleic acids
•remaining parts of S.I. are the jejunum and ileum where
nutrients are absorbed by finger-like projections = villi
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Auxiliary Organs
• pancreas releases proteases, amylases, and lipases into
S.I.
• liver produces bile (stored in gall bladder) that contains
salts to break up fats
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• 6) Large intestine – colon, absorbs water,
remaining feces are expelled, bacteria live here
• at the top a projection there is a projection called
the appendix, in herbivores it is called the cecum
and aids in cellulose digestion
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• gastrin – made by
stomach lining,
stimulates cells to make
gastric juices, responds
to smell and sight
• secretin – made by S.I.,
causes pancreas to
make bicarbonate to
neutralize chymes
acidity
• cholestokinin – made by
S.I. and stimulates gall
bladder to release bile
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Ch 42
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Transport, exchange of blood, gas, nutrients,
waste
Open circulatory system – pumps fluid through an
internal cavity  blood bathes tissues with
nutrient rich fluid called hemolymph, ex. insects,
mollusks
Closed circulatory system – pumps blood through
vessels to tissues, ex. vertebrates, annelids
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Arteries – vessels carrying oxygenated blood
away from the heart, (direction is the key)
Exception- pulmonary artery – oxygen
poor
blood
Arterioles – small branches of arteries, branch into
Capillaries where exchange occurs by diffusion (O2,
CO2, waste)
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Vein- vessels carry deoxygenated blood
to the heart and to the lungs
Exception – pulmonary vein – oxygen
rich
Venules – smaller branches of veins
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Right atrium – deoxygenated blood enters via
anterior & posterior vena cava
AV valve (tricuspid) – keeps correct blood flow,
“lub”
Rt. ventricle – strong, contracts to pump blood out
Semilunar valve - prevents backflow, “dub”
Pulmonary artery- oxygen low blood to the capillaries
in the lungs, gets O2
Pulmonary vein (high oxygen)→Left atrium→ left AV
valve, left ventricle aortic semilunar valve
Aorta (largest artery), coronary artery is here and
supplies blood to the heart itself, blood now goes
through arteries to the body
Exchange of oxygen and CO2, diffusion
Veins carry blood to the vena cava, to the rt. atrium
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Double circulation – look p874
Pulmonary circuit = blood moves from the heart
→lungs →heart, gets O2
Systemic circuit = blood moves through the body,
loses oxygen
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Systole – contraction of the heart
Diastole – relaxation of the heart
Cardiac output = volume per minute of the left
ventricle = 5.25 L/min = volume of blood in the
body
Heart’s rhythm is regulated by autorhythmic cells
Diastole - SA node (sinoatrial) or pacemaker (top of
Rt. Atrium) signals contraction of the atria, delayed
impulse to AV node
AV node stimulates purkinje fibers,ventricles
contract
Systole - blood forces through p. artery and aorta,
AV closes , surgery
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ECG – measures the electric current
Initial pressure starts via the heart, aided by
the smooth and skeletal muscles that
surround vessels
fig 42.10– bp
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Returns lost nutrients back to the blood
through lymph nodes
lymph filters the blood and removes "things"
in conjunction with the immune system, 4L a
day
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1) Red blood cells (erythrocytes) - 25 trillion,
transport O2, no nucleus, anaerobic, live 3-4 months
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2) White blood cells (leukocytes) - diseasefighting cells, # varies
3) platelets - help clot blood with fibrin
4) plasma - 55% of blood, mostly fluid of water,
waste, nutrients
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Mechanisms
 1) Direct with environment - cells directly exchange
gasses by diffusion, ex. flatworms
 2) Gills = outgrowths from the body to increase
surface area and exchange gas, common in fish
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countercurrent exchange between water &
blood, p888
3) Trachea - chitin lined tubes found in insects, gas
moves through openings called spiracles
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4) Lungs - cavities within the body, ex. mammals
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gas enters the nose - warmed and cleansed by hairs
moves through pharynx and larynx (voice box)
trachea = cartilage lined tube, covered by epiglottis
trachea splits into bronchi which enter lungs and
continue to branch into smaller tubes = bronchioles
bronchioles end at alveoli, which are air sacs
surrounded by blood carrying capillaries
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here diffusion take place
between alveoli and the
blood, CO2 diffuses out into
alveoli and O2 diffuses in
the blood transports the O2
via hemoglobin in the RBC,
the O2 binds with iron, baby
oxygenated blood goes to
the body tissues and
diffuses in
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CO2 is moved as bicarbonate ions (HCO3-) – ph
air is moved through the lungs by the diaphragm =
large muscle under the lungs, and intercostals
muscles = muscles between the ribs
diaphragm relaxes, increases pressure in the lungs
and air moves out
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diaphragm contracts, decreases pressure, air
moves in
Total lung capacity is 6 L, at normal breathing
rate about ½ L goes in, and ½ L goes out = tidal
volume
Vital capacity = huge breath = 4800 ml
Reserve capacity = 1200 ml, can’t rid of this air
at rest we breath 12 x a minute
controlled by chemoreceptor in the carotid
arteries that monitor pH, the more CO2 = more
acidic pH, which increases breathing rate
this is a negative feedback loop
loading and unloading – p893-894
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