UF BSC2011 EXAM 2 ANIMALS

what puts constraint on animal form and function?

evolution and natural selection

ICF

intrecellular fluid. the fluid that is contained in cells. makes up 2/3 of the body's water

ECF

extracellular fluid. makes up the remaining 1/3 of the body's fluid. 75% is interstitial fluid, 25% is plasma.

advantages of multicellularity

allow for complex organisms to evolve because different cellular functions can exist.

allows cells a better chance at surviving because they can rely on eachother

what are the two barriers?

cell membranes: a barrier into and out of the cell

epithelia: control movement into and out of organs and tissues

epithelial tissue

protect, absorb, secrete

line the insides of organs and blood vessels and the outside of the body. SENSORY FUNCTION

nervous tissue

signal transduction, communciation throughout the body.

muscle tissue

movement and support

connective tissue

serves to connect the entire body. adipose tissue, blood, bones. also helps with support

the type of connective tissue is determined by concentration of ECF

central theme of physiology

homeostasis

positive feedback

amplifies the stimulus that creates the error message

birth, urination, sexual climax, molting

negative feedback

the response serves to dampen the stimulus that is creating the error message. examples are some hormone pathways, temeprature, stress levels (cortisol)

endotherms

get heat from metabolic processes. regulators. increased metabolic rate to compensate for temperature changes in environment and the need to regulate their internal temperature.

ectotherms

regulate their temperature to that of the environment. have low metabolic rates, but they do increase slowly as temperature increases.

cellular respiration

12h2o+6co2=glucose+6O2

what happens to CO2 in water

it becomes carbonic acid, which then dissociates into bicarbonate and ions, which go to the lungs, reform CO2, and get breathed out

what way does gas flow

down the partial pressure gradient

what percent of air is oxygen

21%

what gas diffuses more easily into water?

CO2 because of dipoles

oxygen

oxygen is easier to get from the air because air is less viscous and less dense than water, air also contains about 20X the amount of oxygen as water.

summary of the transport of gases in the body

inhalation (bulk flow)

diffusion across epithelial cells

circulation (bulk flow)

diffusion across epithelial surfaces into tissues

ficks equation

q=da(p1-p2)/l

q=flow rate

d=diffusion constant

a=cross sectional area of membrane

p1-p2=pp difference

l=membrane thiccness

kroghs rule

states that oxygen can diffuse over distances smaller or equal to .5mm

flatworms and sponges (breathing)

kroghs rule. rely on simple diffusion

how do amphibians breath

through their skin (high water loss, but works in water and in the air)

close their mouth to use positive pressure to get air into lungs. countercurrent gas exchange in vessels. bidirectional/tidal air flow.

how do birds breath

unidirectional air flow over respiratory organs. increases partial pressure difference

first breath: air is breathed in and goes to posterior air sacs

first exhale: air is moved from posterior air sas into parabronchi where gas exchange takes place

second inhale: air moves from parabronchi/lungs into the anterior air sacs

second exhale: air is moved out of the bird from the anterior air sacs

birds also have the most efficient respiratory system. they have the thinnest epithelial tissue

countercurrent gas exchange.

how do mammals breathe

negative pressure breathing caused by the diaphragm contracting to pull air into the lungs. countercurrent gas exchange. tidal ventilation. tidal ventilation results in some mixing of air which makes it slightly inefficient.

how do fish breathe

fish use gills which have gill filaments and lamellae. fish force water over their gills and utilize countercurrent gas exchange to extract O2 from the water. UNIDIRECTIONAL

circulatory systems mediate the flow of (6)

gases, salts, hormones, heat, glucose, water

placozoans and flatworms circulatory systems

none because of kroughs rule

nematode circulatory system

open, fluid flows between the two body tubes

arthropod circulatory system

open

vertebrate circ system

need true circualtory systems

elements of a true circulatory system

pump, conduits, fluid. REQUIRES MORE ENERGY THAN OPEN

open circulatory systems

blood and interstitial fluid mix. arthropods, mollusks, insects

hemoglobyn and hemocyanin

use iron/copper to bind O2 to transport because O2 can not diffuse into water

what does a series mean

refers to the order of blood flow, is needed to effectively transport and allow oxygen to diffuse

fish circ system

two chamber heart. only one circuit. blood flows from heart into afferent arterioles. flows to gill capillaries to pick up oxygen. flows to efferent arterioles into the systemic circuit. flows back to heart

reptile circ system

three chambered heart with two atria and one ventricle, although in reptiles the ventricle is largely split. two circuits. deoxygenated blood flows into the right atria, into the ventricle, and then into the pulmonary circuit. oxygenated blood then flows from the lungs to the ventricle again, and then is pumped into the systemic circuit. are able to shunt blood from lungs when needed.

amphibian circ system

three chambers, two atria and one ventricle. one ventricle means oxygenated blood and deoxygenated blood mix which makes it less efficient. deoygenated blood flights into the right atria and into the ventricle, then to the lungs to pick up oxygen. flow back into the left atria and then to the ventricle and then is pushed into the systemic circuit.

mammal and bird circ system

four chambered heart with two atria and two ventricles. this is the most efficient which is good because birds and mammals are endotherms. two circuits. two atria two ventricles. deoxygenated blood flows into the right side and flows to the lungs to pick up oxygen. flows back into the left side, and flows to the systemic circuit.

explain teh path of bloodflow in mammals

deoxygenated blood enters the right atria from the venae cavae. it flow into the right ventricle, passing the AV valve (prevents backflow) the blood is then pushed into the pulmonary artery from the ventricle, passing the pulmonary valve. oxygenated blood then returns through pulmonary VEIN to left atria, passes into ventricle passing the AV valve. blood then passes into the aorta and flows into the systemic circuit

order of conduits

arteries-arterioles-capillaries-venules-veins

explain how a heartbeat spreads

pacemaker cells held in the SA node begin signals, which is then held up at the AV valve to allow blood to fill ventricles (AV valves close). the signal then passes to the apex of the heart through AV BUNDLE. the ventricles then contract

DEPOLARIZATION before contraction

blood flow physics details

the BP is highest in the aorta coming out of the heart. arteries have higher BP than veins. as conduits get smaller, the liquid flow rate decreases to allow for O2 diffusion in capillary beds. at capillaries, cross sectional area is largest because of the capillary beds. BP picks up slightly in veins

veins

have valves. low flow rate. flat cross sections. can act as blood reservoirs. carry blood to heart. deoxygenated blood.

Exception: pulmonary vein has oxygenated blood OTW to heart

what is the relationship between liquid flow rate and vessel diameter

as diameter decreases, resistance increase and flow rate decreases.

arteries

can change diameter as needed. higher BP than veins. have smooth muscle lining to change diameter. round cross sections. have elastin fibers. carry blood away from heart. oxygenated blood

exception: pulm artery has deoxygenated blood OTW to the lungs

vasoconstriction vs vasodilation

vasoconstriction is caused by smooth muscle. this decreases the blood flow to an area. vasodilation increases the blood flow to an area. this allows the organism to choose where to send blood

____ ____ interactions cause muscle movement

protein protein

why do muscles work in opposing pairs

because htey can ONLY contract, they are incapable of 3D movement

sarcomere

the functional unit of muscle.

myofibrils

made up of myofilaments (which contain actin and myosin)

held together by conn tissues

why are skeletal muscle cells multinucleated

because they are a combination of embryonic precursor cells called myoblasts which each had their own nucleus

which bands on the sarcomere change during a contraction?

I and H

muscle cells use ______ and _____ to regulate contractions

action potentials and calcium

what are the six steps of a neuromuscular junction

an action potential spreads from a neuron to the neuromuscular junction which causes voltage gated Ca channels to open which stimulate the release of acetylcholine (skeletal, but it is norep in cardiac) which

opens ligand gated Na channels

depolarization spreads throughout the muscle cell through voltage gated Na channels, spreads down t tubules. voltage gated Ca channels open. Ca released into cytoplasm

explain the role of action potentials and calcium in muscle contraction

APs are propogated from a neuron, which signals the release of neurotransmitters into the synaptic cleft. neurotransmitters open Na channels, which signal to the cell to release calcium. calcium travels down the T tubules and binds to troponin, which moves the tropomyosin and exposes actin binding sites. myosin then binds to actin and releases an inorganic phosphate, causing a powerstroke. this continues. the contraction stops once the calcium has been removed , ATP is released, and the myosin detaches from actin.

T tubules in skeletal muscle

help propogate action potentials, extend into the saroclemma.

type of muscle contracitons of each type of muscle

cardiac: myogenic

smoothe: involuntary

skeletal: voluntary

intercalated discs

connect cardiac muscle cells

gap junctions

connect smooth and cardiac muscle cells to help propogate contraction-- the cells are connected through their cytoplasms

pacemaker cells

begin the contraction in cardiac muscle.

notes on smooth muscle

no sarcomeres because smooth muscle contracts in sheets instead using gap junctions of using the sliding filament model. found on the insides of hollow organs such as the uterus and intestines. can dilate or constrict blood vessels.

parts of a neuron

soma: cell body, big round part

dendrites: the extensions

axon: the single long extension

axon hillock: where the axon connects to the cell body (AP fired here)

axon terminals: end reaches of the axon

concentration of ions in the neurons

there is more POTASSIUM on the inside of the cell, more SODIUM on the outside

Na-K pump

3 Na out, 2 K in

why us the resting potential negative?

leaky POTASSIUM channels--K flows out of the cell

resting potential:

-65 mv. leaky channels are open

depolarization:

cell becomes less negative, sodium flows into the cell

repolarization

at 40 mv, sodium channels close and K channels open, leading to potassium flowing out of the cell. the cell then becomes more negative.

hyperpolarization

once resting potential is reached, K channels close, but the cell over shoots and becomes overly negative. allows for refractory period. fixed by Na K pump.

how to speed up AP propogation

increase the diameter of the axon or use myelin sheath. APs are self propogating and move when the next cell is depolarized.

nerve net

simple. no CPU. in cnidarians and echinoderms.

molluscan nervous systems

cephalized, centralized. anterior brains.

motor (efferent) division of the peripheral NS is broken into

somatic: voluntary.

autonomic: involuntary- heartbeat, breathing, etc

ANS divisions

sympathetic and parasympathetic

sympathetic nervous system

fight or flight. skeletal muscle is used. fast heartbeat. inhibits digestion. dilates pupils. sexual stimulation. fast breathing

parasympathetic division

rest and digest. blood goes to digestive system. orgasm. slower breathing

examples of when the body uses the nervous system

panic (seeing a bear) pain response (burning hand) anything that needs a quick response. use action potentials to communicate

when would the body use the endocrine system

growth, stress, pregnancy. any long term changes.

autocrine signaling

the cell communicates with itself

paracrine signaling

the cell communicates with nearby cells

pheromone signaling

chemical signaling to a different organism (outside of organism)

neurotransmitters vs hormones

NT: used to communicate with adjacent cells, cause post synaptic potentials (small)

hormones: travel through blood stream

peptide hormones

can be created ahead of time. stored in vesicles. short half life. attach to the outside of the cell membrane using receptors. released when stimulated HYDROPHILIC

ADH

steroid hormones

hydrophobic. long half lives because they are bound by carrier proteins. can bind to nuclear or cellular membrane. CORTISOL

amines

can have characteristics of peptides or steroids.

neuro secretory cells

controlled by neurons, send message to endocrine tissue

non neural secretory cells

are controlled by hormones themselves. epithelial

pancreas etc

where do most endocrine signals begin

hypothalamus

anterior pituitary

made mostly of non neural cells. releases TROPIC hormones. ACTH

types of hormones released by hypothalamus

releasing or stimulating hormones. go to anterior pit which releases its hormones. CRH

posterior pituitary

axons of neural sectretory cells. releases hormones that act directly on target

what are tropic hormones

hormones that have other endocrine glands as their targets

ADH

distal tubules.

high ADH=lots of aquaporins

negative feedback loop

diuresis

produces a lot of dilute urine. low ADH, few aquaporins.

anti diruresis

low amounts of very concentrated urine. a lot of aquaporins, high ADH. conserves water.

U/P ratios

all animals can make dilute urine (U/P<1) but only mammals and birds can make concentrated urine (U/P>1, dilute ECF)

why does the amount of water availabe determine how an organism gets rid of ammonia

ammonia water soluble and therefore is easier to apss the more water an organism has