Div. Third Test

heterotrophic

need to ingest organic molecules to survive; animals are

types of feeding (4)

predation, herbivory, suspension feeding, symbiosis

suspension feeding

small particles suspended in water are filtered/ collected by gills; particles include algal cells, larvae, dead organic matter

symbiosis

food obtained from microbial symbionts; ex. corals

why must animals eat essential nutrients throughout their lives?

molecules in body formed from molecules in food; animals can’t make all molecules they need from food conversions so they have nutrients they have to consume

essential nutrients

nutrient animal needs but cannot make itself; ex. some amino acids, vitamins

elements required by animals in food

calcium (bone, nervous system), phosphorus (nucleic acid, ATP), potassium (nervous system), sodium (nervous system, water balance)

metabolic rate

amount of energy animal converts to heat each day; more energy consumed (higher rate) means more food consumption to replace

measuring metabolic rate

1:1 ratio of rate of oxygen used to rate of heat produced

fundamental reason animals need energy

obtained as chem bonds and broken to use and release heat

BMR

metabolic rate while resting

exercise and metabolic rate

physical activity uses more energy > higher metabolic rate > higher oxygen consumption > higher heat production

size and metabolic rate

smaller animals need more food per gram of body weight

division of labor

cells are specialized for a particular function; animals have high amount

simple epithelium

sheet of cells covering surface or organ or lines body cavity enabling compartmentalization; one cell thick and enables movement of solutes and components through; close to blood vessels to get things into the blood; lines intestine

circulatory system in digestion

delivers nutrients to systemic tissues

digestive tracts and different diets

herbivores have longer intestines for storing large amounts of plant materials; carnivores have reduced cecum

basic functions of nervous system (3)

sensory input (receptors), integration (thoughts, memories, decisions, sensation), motor output (effector organs)

neuron structures

cell body, dendrites, axon, axon terminals

dendrites

input region; convert chemical signals to electrical signals

cell body

integrates incoming electrical signals

axon

conducts electrical signals

voltage

potential energy stored; different concentration of ions stored across cell membranes

current

released potential energy; flow of charge between points through ions moving

resting membrane potential

inside of cell more negative than the outside (has less positively charged ions)

how is negative resting membrane potential established?

Na K pump (3 Na out, 2 K in/ uses ATP); differences in permeability (leak channels, especially K leaking)

graded potential

required to initiate AP; excitatory or inhibitory; stimulus opens LG channels; short distance signaling (current decreases with distance); variable strength (more points of input = stronger); small region of membrane

action potential

with VG channels (inside cell more positive than outside); long distance signaling (doesn’t weaken with distance); constant strength (all or nothing)

AP depolarization

local currents depolarize and summate to threshold; all VG Na channels open; membrane potential becomes more positive

AP repolarization

VG Na channels inactivated, VG K channels open; K flows out of axon

hyperpolarization

K channels open longer than needed, Na K pumps resting

AP propagation

signal moves like a wave down the axon

saltatory conduction

axon fibers myelinated to prevent Na leaking; provides insulation so ions outside aren’t electrically attracted and slow down AP; openings/ nodes for ions to come through; increases conduction speed

excitatory neurotransmitters

make inside of cell more positive

inhibitory neurotransmitters

make inside of cell more negative

EPSP

make postsynaptic AP more likely; depolarization, Na inflow

IPSP

make postsynaptic AP less likely; hyperpolarization, K outflow or Cl inflow

simultaneous EPSPs and IPSPs

cancel each other out; simultaneous Na inflow and K/ Cl outflow

transduction

conversion of energy from one form to another; transforms stimuli into electric signals to travel to brain

first step in transduction in receptor cells

graded potentials generated; potential stronger with more stimulation

second step in transduction in receptor cells

AP generated in neurons; transmission; stimulus energy relayed to integrative parts of nervous system for interpretation

two types of receptor proteins

ionotropic and metabotrpic

ionotropic

receptor protein is the ion channel; directly generates graded (receptor) potential

metabotropic

receptor protein relays signal through G protein mechanism to a channel; uses second messengers like cAMP; indirect generates graded (receptor) potential

labeled line code

any info pathway responsible for only one type of sensory info

sensory info going to brain

neurons extend from receptor cell to processing region (different functional areas in brain to interpret different sensory info)

olfaction

has metabotropic receptors; has odorants which chemoreceptors detect; GPCRs diverse for each smell; mucus traps chemical odorants

simple vs complex vision

light and dark vs detailed, often colored images

visual opsins

receptor proteins; include a protein (opsin) and 11-cis-retinal which absorbs light (derived from vitamin A)

general pathway of photoreceptors and vision

opsin absorb light photons > change shape > causes opsin to change shape > activates G-protein > graded potential > AP

photoreceptors

sensitive to light; hyperpolarize neurons

arthropod vision

compound eyes where brain compiles image integrating info from all ommatidia (like pixel density in monitors)

ommatidia

optical units on eye; each has lens and photoreceptor cells; more = higher resolution; in arthropod vision

sensory systems humans cannot use

electromagnetic wavelengths we are blind to, electric fields

electromagnetic wavelengths in sensory

humans see 400-700 nm; above is infrared (snakes see), below is ultraviolet (birds and bees see)

electric fields in sensory

perceive surroundings and communicate using electric fields in place of visual info; ex. electric fish

muscles

unique to animals; convert energy from ATP to mechanical movement

skeletal muscle

attached by tendons to bones, packed with actin and myosin; for locomotion; has troponin as receptor for Ca+; long and striated, voluntary; adaptable

cardiac muscle

shorter cells, branched, interlinked network; has intercalated disks between adjacent cells to connect them; involuntary

smooth muscle

actin and myosin arranged in loose network instead of bundles; has calomodulin as receptor for Ca+; involuntary

titin

anchors myosin; elastic property works as spring mechanism when muscle relaxes

additional structures in skeletal muscle cells

multinucleate, t-tubules, sarcoplasmic reticulum, myoglobin, glycosomes (store glucose)

myosin

chains twisted together; have heads and tails

actin

two chains twisted; myosin head binding sites; has troponin (moves other when Ca attaches) and tropomyosin (covers attachment sites at rest)

excitation

when a nerve impulse arrives at a neuromuscular junction and initiates an action potential

excitation-contraction-coupling

process where electrical excitation of membrane leads to contractile activity by proteins

neuromuscular junction

a synapse where a motor neuron axon makes contact with a muscle fiber

initiation of contraction

motor neuron is stimulated sending signal towards muscle fibers, ACh released and diffuses across gap, creates AP in muscle fiber; AP spreads away from junction