module 3 (exam 2) - animal diversity Flashcards
name 5 important characteristics that define an animal
multicellularity (and cell specialization)
heterotrophic metabolism (eating other organisms)
internal digestion
ability to move
nervous systems
what 5 important characteristics allow animals to survive?
eat nutrients & take in oxygen
expel waste
protect themselves
grow
reproduce
what is the ancestral form of symmetry? who/where is it present?
spherical symmetry - present in some protists but no animals
define radial symmetry
symmetry in that any plane along the central body axis can divide the animal into similar halves
define bilateral symmetry
a single plane through the anterior-posterior midline divides the animal into near-identical halves
what do radial and bilateral symmetry have in common?
in both, animals typically have an anterior (associated with mouth) and posterior
which form of symmetry is associated with greater mobility?
bilateral symmetry
what are the 2 types of digestive systems?
sac design and tube
give main characteristics of sac design digestive systems (3)
one one opening for both eating food and excreting waste
no specialization for ingestion/regurgitation
small and thin
give main characteristics of tube digestive systems (1)
two openings - mouth for eating and anus for excreting
ex. humans
what are the 3 different strategies of body cavities
acoelomates, pseudocoelomates, and coelomates
what defines an acoelomate?
no coelom - no cavity but rather filled with masses of cells
do acoelomates have an easy or difficult time moving around? what do they use for locomotion?
more difficult to move because no open body cavity
use cilia to move
what defines a pseudocoelomate?
the coelom is not completely enclosed by the mesoderm
the pseudocoel (cavity) is filled with fluid
what defines a coelom?
a body cavity & internal organs fully surrounded by mesoderm
what main ability differs between organisms with body cavities and those without?
animals without a body cavity have a more difficult time moving around than those with body cavities
T or F: most animals are at least partially segmented
true
what are the benefits of segmentation? (3)
allows specialization of body regions
helps change body shape
changes in segmentation allowed radiation of arthropods
do humans have segmentation?
yes - some
abdominal muscles are segmented
what are 5 types of appendages & their uses?
feet (locomotion)
hands (for grasping/using tools)
antennae (sense organ)
claws/mouth appendages (eating)
appendages for transfer of sperm/egg incubation
why are nervous systems essential in animals?
allows for the coordination of movement and gives sensory systems a way to process
how does a nerve net work?
there is no central processing center (like the brain), but it can still relay, sense, and react
what is the proposes pathway for how colonial protists became multicellular animals? (6 steps)
adherence of cells –>
cell specialization –>
further differentiation of cells –>
cell coordination/communication –>
increase in size of animals –>
increase in complexity of animals
cells in animals are adhered to one another and arranged into what?
tissues
what ability does adherence of cells give tissues so they may be successful?
cells can stick to each other and to the extracellular matrix
what are the molecules (2) that allow cells to stick?
Cell Adhesion Molecules (CAMs) and integrins
what is the purpose of integrins?
they attach a cell’s cytoskeleton to collagen (& other proteins) in the extracellular matrix
how do integrins function?
it has binding sites for the cell cytoskeleton and extracellular matrix so that the cell is bound to the matrix
when integrin’s 3-D structure changes, what is the result?
it can no longer bind to the EXM & the cell detaches
what are the 3 types of animal cell junctions?
tight junctions, desmosomes, and gap junctions
what is the function of tight junctions?
they prevent materials from the ECM from moving between the intercellular spaces of epithelial cells
no molecule movement
what is the function of desmosomes?
they bind cells tightly but allow some materials to move between intercellular spaces & within cell membranes
what is the function of gap junctions?
pores that allow adjacent cells to exchange material
important for coordination & communication between cells
what are the 4 purposes of epithelial tissue ?
lining or covering with barriers, exchange of molecules, communication, and coordination
what is the purpose of muscle tissue?
movement and generating force
what are the 3 types of muscle?
skeletal, cardiac, and smooth muscle
what 5 things characterize skeletal muscle?
multinucleate, striated, voluntarily moved, moves quickly, and is meant to take breaks every so often
what 4 things characterize cardiac muscle?
cells are coordinated by gap junctions, some striations, acts in rhythmic fashion, has continuous movement
what 4 things characterize smooth muscle?
some tissues have gap junctions and others not, not striated, involuntary regulated by nervous system, moves slowly
what characterizes connective tissue?
typically has fewer cells and more extracellular matrix (often with protein fibers like collagen and elastin in the matrix)
where is connective tissue found in the body?
adipose (fat), cartilage, bone, and blood
what is the purpose of connective tissue?
storage, structure, movement, and flexibility
what is the purpose of the nervous system?
communication (fast electrochemical signals), sensory, and coordination
define an organ
2+ tissue types arranged in a particular way to perform a particular function/set of functions
define and organ system
individual organs are a part of a system that works together for particular functions
define cephalization
the concentration of sensory organs and nervous tissues at the anterior (head) end of an organism
what form of symmetry is often found with cephalization?
bilateral symmetry
give 4 reasons why movement is essential to an organism
finding a mate
acquiring food
avoiding predators
finding a suitable habitat
what is bipedal locomation?
ability to walk on 2 legs
how do humans benefit from bipedal locomotion? (3)
can carry more things
saves energy
can see at a taller frame
where is most water in the human body found?
intracellularly
what is the main benefit of having extracellular fluid?
cells get nutrients from it and can remove waste into it
extracellular fluid is also known as what?
the internal environment
define homeostasis
stability of the internal environment of an individual allowed by internal coordinated processes
OR anything that means consistency or stability in an organism
why does epithelium play a role in homeostasis?
it is closest to the external environment
what are the 2 approaches to achieving homeostasis?
conformation and regulation
how do the bodies of organisms regulate heat exchange in skin?
blood vessels constrict or dilate depending on the temperature
how do blood vessels change shape when it is cold?
vessels near the surface constrict to reduce heat loss
more internal vessels dilate to allow blood to bypass the colder surface vessels
how do blood vessels change shape when it is hot?
vessels near the surface dilate to lose heat
more internal vessels constrict to push blood toward the skin’s surface
name a few parameters of homeostasis (7)
temperature regulation
pH
behavioral responses
concentrations of O2, CO2, and Na+
blood pressure
heartbeat & respiratory rate
blood fluids
what does the Q10 temp coefficient measure?
the sensitivity of a reaction or physiological process to a change in temperature
what is the Q10 temp coefficient?
Rate of reaction at temp A
divided by
Rate of reaction at temp A - 10º
define homeotherms and give examples of them
animals that keep a steady internal body temp (warm-blooded)
ex. birds and mammals
define poikilotherms and give examples of them
animals that vary their body temp along with the environment (cold-blooded)
ex. frogs, lizards, fish
homeotherms have a ______ (higher/lower) metabolic rate than poikilotherms, no matter the external temp
higher always
reindeer are hometherms - how do they survive in extreme temperatures?
natural insulation with thick fur & hollow hairs full of nonmoving air (nonmoving air is warmer than moving air)
define an endotherm
an animal that primarily gets heat from internal sources (metabolism)
define an ectotherm
an animal that obtains heat primarily from external sources
endotherms have membranes that leak ions _____ (more/less) than ectotherms
more
what kind of tissue (+ 2 colors) do homeotherms have to keep them warm? which color of this tissue produces heat?
brown and white adipose (fat) tissue
brown produces heat
define nonshivering thermogenesis
an increase in metabolic heat production derived from metabolizing brown fat tissue
what types of organisms typically have the nonshivering thermogenesis mechanism?
small mammals
what 3 locations in the body is brown adipose tissue located?
heart, kidney, and vertebral column
why do some small animals utilize a protective microenvironment
to stay warmer - nonmoving air closer to the ground is warmer than moving air
define acclimatization
give 2 examples
an adjustment of behavior and/or physiology to be better suited for the environment
ex. reindeer metabolize slower in the winter
ex. humans wear more clothes when it’s cold
define regional hypothermia
a phenomenon in which the appendage tissues of an animal are cooler than body core tissues
what is the purpose of regional hypothermia?
body heat is conserved by only keeping core body tissues warm & because they’re already cold, appendages don’t lose heat when walking on ice or snow
define countercurrent flow
an exchange of heat that occurs between 2 closely positioned fluid streams (i.e. blood streams) flowing in opposite directions
what are two animal mechanisms for releasing heat by evaporative cooling?
panting and sweating promote loss of heat
what are the 4 main mechanisms of external heat exchange?
radiation
convection
conduction
evaporation
define convection in terms of heat exchange
the process of heat transfer (in fluids/gases) by the movement of matter
define evaporation
removal of water from body surfaces/breathing passages by the environment in order to cool down
define hibernation
a state with low body temps and thermal conformity persisting for long periods of time (typically in winter)
which types of animals are most likely to hibernate?
small mammals
define heterotherms
homeothermic animals during summer but hibernate (cool down body temp) in winter
how does body temp change during hibernation?
becomes similar to external environment temperature
define thermoregulation
ability to control one’s own body temperature
adaptations for thermoregulation are likely driven by what?
changes in DNA
animals have what kind of metabolism?
heterotrophic metabolism
it is important to eat because each cell in our body breaks down & rebuilds what % of protein molecules every day?
2-3%
it is important to eat because each cell uses how many ATP molecules every day?
more than 10^14
name 3 types of feeding by animals
predation, suspension feeding, and symbiosis
define suspension feeding(/filter feeding)
in aquatic animals, a method of obtaining food by collecting small food particles suspended in the water
define symbiosis/a symbiotic relationship
microbes live within the animals’ bodies and synthesize food molecules that are directly transferred to the animals as food
homeostatic mechanisms are dependent on which 2 things?
regulation and feedback
name the 4 components of homeostatic mechanisms
stressor, sensor with receptor, integrator, and effector
define a homeostatic stressor
something that causes deviation away from a set point
what’s the purpose of a homeostatic sensor with receptor?
to detect the error signal produced by the stressor causing a deviation from a set point
what’s the purpose of a homeostatic integrator?
to receive information from the sensor and send compensatory signals to the effectors
define a homeostatic effector
something that produces a change to the internal environment in order to overcome result produced by the stressor
define regulatory system feedback
information about the relationship between the set point of the system and its current state
define regulatory feedforward
changes the set point of a regulatory system in anticipation of a stressor to amplify the response
define regulatory positive feedback
a type of control that acts to increase differences that arise between the level of a controlled variable and its set point
define regulatory negative feedback
a type of control that acts to reduce differences that arise between the level of a controlled variable and its set point
positive feedback usually _____ (stabilizes/destabilizes) a system and negative usually _____ (stabilizes/destabilizes) it
destabilizes, stabilizes
does homeostasis have positive feedback?
no
which region of our body controls body temperature?
the hypothalamus
mammalian birth is an example of what kind of feedback loop?
a positive feedback loop
how does a feedforward system work?
an organism reacts to a stimulus that is not the end product of the pathway by changing downstream responses to the stimulus
high amounts of lac operons being present when lactose is present is an example of a _______ (feedforward/feedback) system
feedforward
high amounts of lac operons being present when glucose is low is an example of a ______ (feedforward/feedback) system
feedback
when there is no lactose present, the repressor does what? why?
binds to the operator so that transcription is blocked and no lactose is metabolized
when there is lactose present, the repressor does what? why?
repressor inactivates and does not bind to the operator - production of allolactose (by reactant lactose) inhibits transcription
what is the purpose of breathing?
to get enough glucose and oxygen to the mitochondria
what is the 4 step pathway of oxygen in the human body?
1) O2 into lungs
2) O2 crosses two layers of simple epithelia
3) O2 moves into blood and down to muscle
4) O2 crosses the blood epithelial wall into cell membrane of muscle cell, then into cytoplasm & enters the mitochondria
what is the 4 step pathway of oxygen in a dog’s body?
1) breathing O2 into lungs and CO2 out by bulk flow
2) a build up of O2 causes diffusion into blood
3) O2 is transported to tissues by bulk flow
4) O2 is taken into mitochondria for ATP production
why do our cells need oxygen?
electrons are released when our body breaks down food to make ATP - the electrons are transferred to O2 molecules
what are the 2 respiratory gases?
O2 and CO2
what are the two ways that air moves into & through the bodies of animals?
bulk flow and diffusion
define bulk flow
the flow of gases from one place to another from an area of high to low pressure
bulk flow is used to transport respiratory gases _____ (short/long) distances and diffusion is used to transport respiratory gases _____ (short/long) distances
long, short
define diffusion
particles move toward a state of equilibrium at random
Fick’s law is used to determine what?
the rate of diffusion per unit of cross-sectional area
what is the formula of Fick’s law?
concentration 1 - concentration 2
divided by
length
what is the 4 step process of alternation of bulk flow and diffusion?
1) bulk flow moves in O2 via breathing
2) diffusion moves particle into lungs and blood
3) bulk flow circulates the blood
4) diffusion of particles out of the blood capillary to the cell membrane, cytoplasm, and mitochondria
define partial pressure of a gas
the part of the total pressure exerted by a certain gas in a gas mixture
what are gas exchange membranes?
location where respiratory gases move between an animal’s environment and their internal tissues
what is breathing (external respiration)
moving O2 into lungs and CO2 out of lungs
what is the importance of large surface areas of breathing organs?
to allow for as much gas exchange as possible
name an animal that completes all gas exchange through their skin (instead of with breathing organs)
lungless salamander
how did gills and lungs evolve to perform more gas exchange?
tissue folding and branching allows for a larger surface area
what is the square area of human breathing membranes?
~130m^2
how are gills folded & branched?
branching and folding outwards
how are lungs folded and branched?
branching and folding inwards
what are the 2 types of air flow direction for breathing?
tidal and unidirectional
define tidal air flow
air flow changes direction in same passages - flows in one way and out the same way
define unidirectional air flow
water (and O2) is pumped one direction - flows in one way and out another
define perfusion
fast blood flow through capillaries or smaller blood vessels of a tissue
what is the benefit of quick blood perfusion?
circulatory system is able to distribute oxygen to cells quicker
does diffusion happen faster in air or liquid?
by how much?
air by 200,000 times
does O2 or CO2 dissolve better in water?
CO2 dissolves much easier than O2 in water
is there higher or lower levels of O2 in warm water compared to cold?
warm water = lower O2
what is the direction of water through gills?
water enters through mouth, over gills, and exits via their opercular cavities under opercular flaps
terrestrial vertebrates mostly have what type of air flow?
tidal air flow (changes direction)
what two types of terrestrial animals have unidirectional air flow? why?
birds and some crocodiles
these animals have rigid breathing structures (volume doesn’t change during inhalation/exhalation)
tracheal breathing systems are found in what kind of animals?
insects
define a tracheal breathing system
in insects - airways (called tracheae) branch throughout body so there are airways near all cells
what is the benefit of a tracheal breathing system?
fast diffusion - O2 is brought right to the cells - no need for a circulatory system
T or F: tracheole tips touch almost every cell in an insect’s body
true
some animals (flatworms & sponges) don’t have specialized breathing organs - why?
because they take in O2 over their body surface
low metabolic rate and most cells are close to the surface
define a trachea (in humans)
principle tube leading into lungs from mouth cavity
human trachea branches into how many tubes?
two tubes - each of which branches out extensively
each final branch in the human lunch has a what?
alveolar sac (with a high surface area)
define conducting airways (in lungs of animals)
airways that do not participate in the exchange of respiratory gases between air and blood, but just move air in and out of the lungs
define respiratory airways
airways in the lungs where O2 and CO2 are exchanged between the air and blood
define tidal volume
how much air can be moved in and out in a mammal’s lung
define resting tidal volume
the normal amount of air exchanged per breath when at rest
define maximal tidal volume
volume about 10x greater than resting tidal volume
define diaphragm
a sheet of muscle connected to the rib cage
at rest, inhalation is _____ (active/passive) and exhalation is _____ (active/passive)
active, passive
define exhalation
elastic recoil of lung tissues - results in relaxed muscles
define inhalation
muscles of diaphragm and some intercostal muscles (between ribs) contract
T or F: during exercise, inhalation is active and exhalation is passive
false - both inhalation and exhalation are active during exercise
breathing is under what kind of feedback by carbon dioxide?
negative feedback control
how does carbon dioxide’s negative feedback control work?
more CO2 = more H+ ion is blood = more acidic blood (bad)
this increase in H+ causes increased ventilation to get rid of CO2 faster to decrease H+ ions
what portions of the brain stem regulate breathing rhythm?
pre-Botzinger complexes (2)
what is the origin of breathing rhythm in humans?
the medulla
T or F: humans can breathe normally with only a portion of the brain stem intact
false: humans need an entire healthy brainstem intact to breathe
what 4 parts of the body is the circulatory system concentrated in?
heart, brain, abdomen, pelvis
define the circulatory system
a pump made of muscle (heart), fluid (blood), and conduits (blood vessels)
what is the purpose of the circulatory system?
to transport materials throughout the body
define a closed circulatory system
blood is contained within the blood vessels - not free in a cavity
define an open circulatory system
blood flows freely through cavities - no vessels to conduct
insects have what kind of breathing system?
what is the purpose of their circulatory systems?
tracheal
insects use circulatory systems for transporting nutrients, not gasses
define a water vascular system
in some marine animals, a network of water-filled canals that functions in gas exchange, locomotion, and feeding in place of a circulatory system
who has closed circulatory systems?
all vertebrates, cephalopod mollusks, and annelid worms
define arteries
large blood vessels that carry blood AWAY from the heart
define veins
large blood vessels that carry blood TOWARD the heart
animals with closed circulatory systems have ____ (high/low) blood pressures to drive flow of O2
high blood pressures (increased metabolic rate)
define the lumen
the space in the center of large blood vessels that blood flows through
describe vascular endothelium
simple epithelium that surrounds the lumen
arteries have elastic tissue and smooth muscle - why?
to allow them to stretch and withstand high pressures
what is the purpose of valves in veins?
to prevent backflow of blood as a result of low pressures
define microcirculation
the part of a closed circulatory system that consists of the smallest diameter blood vessels
what are the three types of small blood vessels?
arterioles, capillaries, and venules
T or F: microcirculation is only found in closed circulatory systems
true
define capillary beds
web-like structures of capillaries where exchange of oxygen and nutrients occur
blood stays in which vessels as it moves through organs and tissues?
microcirculation vessels
where are O2, CO2, and materials exchanged between blood and cells?
in the capillaries
define capillary pores
gaps between endothelial cells (in capillaries)
what is the purpose of capillary pores?
to make exchange of materials easier
what are arterioles controlled by?
the autonomic nervous system (and other mechanisms)
define vasoconstriction
contraction of muscles to make lumen smaller
define vasodilation
relaxation of muscle to make lumen larger
what is the purpose of vasoconstriction and vasodilation?
controls the rate of blood flow
who has open circulatory systems?
arthropods and most mollusks
in an open circulatory system, the heart pumps blood into where?
arteries
define respiratory pigments
blood pigments that undergo reversible combination with O2 and are thus able to carry O2 between different places in the body
give two respiratory pigments and where you find them
hemoglobin - humans
hemocyanin - other animals
define blood plasma
watery solution in which red blood cells and/or other blood cells are suspended - part of the blood other than cells
define red blood cells
a cell in the blood of an animal that contains hemoglobin and transports O2
hemoglobin is a tetramer, which means what?
is has 4 polypeptide chains
every hemoglobin molecule can hold how many oxygen molecules?
4
respiratory pigments reversibly combine with O2 molecules - when are they released?
when surrounding areas have little O2
define the heart
a discrete, localized pumping structure that propels blood
define the myocardium
muscle tissue of the heart
define cardiac output
the volume of blood pumped / minute
define stroke volume
the volume of blood pumped / heartbeat
the heart is myogenic in vertebrates - what does this mean?
the electrical impulse during each beating cycle originates in muscle cells
define a cardiac cycle
a cycle where the heart contracts and relaxes
define blood pressure
the point when the pressure in the blood exceeds the pressure in the environment of the animal
EKG: the P wave corresponds to what?
depolarization of the muscle of the atria
EKG: the Q, R, and S waves (together QRS complex) correspond to what?
depolarization of the ventricles
EKG: the T wave corresponds to what?
repolarization of the ventricles
define systolic blood pressure
no blood flow through arteries at all
define diastolic blood pressure
max pressure that allows continuous flow
define a simple vertebrate system & its path through the body
single circuit: heart –> gills –> body –> heart
define a complex vertebrate system & its path through the body
double circuit: heart –> lungs –> heart –> body –> heart
define autoregulatory mechanisms
each tissue controls its own blood flow
regional autoregulation sets up what kind of problematic feedback?
a positive feedback loop
define atherosclerosis
a buildup of lipids in vessels due to the “breaking” of the circulatory system
in what way does the circulatory system contribute to maintaining homeostasis?
clotting helps animals maintain homeostasis after injury
animals need nutrients for what two main reasons?
building tissue and growth
define dietary minerals
which 4 elements are exempt from the list of dietary minerals but are still required by humans to live?
chemical elements that are required in cells & must be acquired from food exempts oxygen, carbon, hydrogen, and nitrogen
animal growth requires what two things?
fatty acids and amino acids
why do we need to eat continuously?
proteins and other chem building blocks are broken down every day and must be replaced
what are the two forms of required energy?
do they do work?
heat - doesn’t do work
chem bond energy - created by digesting food & is converted to heat
define nutrition
how animals ingest to meet their chemical substance and energy needs
define an essential nutrient
a type of molecule that animals require but can’t make themselves
what are the 4 essential nutrients?
amino acids, fatty acids, vitamins, essential minerals
define metabolic rate
amount of energy the animal converts to heat per day
an animal’s metabolic rate determines what?
how much they need to consume per day
the faster an organism goes, the _____ (more/less) O2 is used and its metabolic rate _____ (increases/decreases)
more, increases
what is basal metabolic rate (BMR)?
a standardized measure of metabolic rate at rest
define a calorie
an amount of heat required to raise the temp of 1 gram of water by 1 degree C
one kilocalorie = how many calories?
1000 calories
proteins cannot be absorbed - how are they taken in then?
by digestive enzymes
define digestion
the breakdown (by hydrolysis) of ingested food molecules into smaller chemical components that an animal is capable of absorbing and distributing to the tissues of the body
define hydrolysis & give an example rxn
A chemical reaction that breaks a bond by inserting the components of water (AB + H2O → AH + BOH)
what are the 4 functions of the digestive system?
digestion, absorption of nutrients, storage, and elimination of waste
what organs does the foregut consist of?
mouth, esophagus, and stomach
what organs does the midgut consist of?
small intestine
what organs does the hindgut consist of?
large intestine & rectum
define salivary glands
glands in mouth that discharge saliva to assist with the breakdown of foods (via enzymes in saliva)
define intracellular fluid
liquid inside of cells
define extracellular fluid
compartmental fluid outside of the cell
define epithelia
sheet(s) of cells that cover bodies or organs
what are 3 functions of epithelia?
pump ions, secretion, and sensing
define cell membranes
separate a cell’s interior from the environment
define division of labor
cells are specialized for particular functions so not each cell has to do everything
define tissue
an assemblage of cells that are a similar type
what is the importance of the midgut in mammals?
majority of digestion and absorption occur here - has a large surface area
define absorption (digestive)
the uptake of products of digestion into the blood
how does the mouth contribute to food processing?
enzymes in saliva begin to break down food
how does the stomach contribute to food processing?
acid and mechanical churning further break down food
how do the intestines contribute to food processing?
small molecules and water are absorbed and transported into the blood
define a ruminant
hoofed herbivorous grazing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion via microbes
why did ruminants evolve?
no vertebrate animal has enzymes alone that are able to digest cellulose - ruminants’ symbiotic relationship with microbes in their stomachs allow them to obtain nutrients from cellulose
what kind of feedback system is the process of maintaining a constant blood glucose level?
negative feedback system
how does the body fix a too low blood glucose level?
detection –> pancreas secretes glucagon (alpha cells) –> glucagon is broken down in the liver –> glucose is released into blood & blood glucose levels rise
how does the body fix a too high blood glucose level?
detection –> pancreas secretes insulin (beta cells) –> stimulates uptake of glucose by cells –> glucose is used for metabolism, fat synth, and glycogen synth & blood glucose drops
what is type 2 diabetes?
a resistance to insulin –> leads to too high blood glucose levels
what parts of the human body comprises the central nervous system (CNS)?
the brain and spinal cord
what parts of the body comprises the peripheral nervous system (PNS)
everything besides the brain and spinal cord
how are spinal nerves organized?
come in pairs, one on each side of body along the length of spinal cord
what are other types of nervous systems other than a humans?
nerve nets & ganglia
what 5 things does the nervous system control?
sensory, integrative, analytical, homeostatic, and motor functions
define neurons & their shape
nerve cells - small & have elongated shape
define nerves
nerve bundles in the PNS
define sensory neurons
neurons (individual cells) that carry signals from sense organs to the CNS
define motor neurons
neurons that carry signals to muscle cells
how fast do mammals’ neurons transmit signals?
20-100 meters per second (<.02 seconds)
neuron cells are fast & addressed - define addressed
signals are sent to specific target cells
what defines an excitable cell?
their cell membranes can generate & conduct impulses or action potentials
which cells are excitable?
only neurons in muscle cells
define action potential
a state of reversed polarity of a cell membrane
define depolarization
when the electrical polarity of a cell is changed - the inside of the cell is less negative (or now positive)
define membrane potential
a charge difference across a cell membrane - accumulation of positive or negative charges near the membrane on either of its sides
define resting membrane potential
when cell is at rest - membrane potential when its not firing an action potential
T or F: resting potential takes energy to maintain
true
define propagation/conduction
the process of action potential (reversed polarity) moving along the cell membrane in one direction
define an axon’s current
the flow of electric charges from place to place
define an axon’s voltage/potential difference
positive charges are connected in one place and negative charges are connected in a different place
action potentials travel along what?
axons
name 4 common anatomical features of neurons
set of dendrites
cell body
axon
set of presynaptic axon terminals
define a synapse
the junction between a neuron and its target cell that allows for communication
define a presynaptic cell
cell that conducts signals INto synapse
define a postsynaptic cell
cell that conducts signals AWAY from synapse
define dendrites of neurons
short cell processes/extensions that branch from cell body
define a neuron’s cell body
has neuron’s nucleus and organelles and integrates signals
define a neuron’s axon
long cell process for long-distance signal conduction
define a neuron’s presynaptic axon terminals
swelling at end of axon that makes contact with other cells
define myelin
concentric layers of cell membrane that wraps around a neuron’s axon
what are two types of glial cells that electrically insulate an axon?
oligodendrocytes
Schwann cells
define white matter
what is it named for?
parts of a nervous system with mostly myelinated axons
named for its glistening white appearance
name 3 types of neurons
interneurons
sensory (afferent) neurons
motor (efferent) neurons
what is the significance of interneurons?
they are confined to the CNS
make up most neurons of the CNS
what are the functions of interneurons?
command & information-storage functions
what are the functions of sensory neurons?
carry signals to CNS from sensory cells/organs
what are the functions of motor neurons?
convey signals from CNS to effectors like muscles & glands
define a glial cell
a type of cell found in the nervous system that are not neurons
T or F: glial cells are excitable and can conduct action potentials
false - glial cells are not excitable and therefore cannot conduct action potentials
what are 3 functions of glial cells in the brain?
metabolic support for neurons
regulating extracellular fluid composition
immune functions
what is the function of glial cells in development?
they guide growing neurons in the CNS
what is the most abundant cell in the brain?
astrocyte glial cells
what is a neurotransmitter?
tiny chemical compound molecules that are released from the end of a presynaptic cell to the postsynaptic cell
neurotransmitters can do 2 things to a postsynaptic cell - what are they?
excite or inhibit
what are 3 common neurotransmitters?
norepinephrine
dopamine
serotonin
sense organs detect…
physical or chemical stimuli in the environment
what detects sensory stimuli?
receptor proteins
reception of stimuli results in… (2 answers)
an action potential in receptors cell OR in a release of a signal that eventually produces an action potential in a neuron
define sensory receptor cells
cells (usually neurons) that transform energy of a stimulus into an electrical signal
define transduction (sensory)
a sensory receptor cell produces an electrical signal from the produces stimulus energy
a rod cell’s membrane in the light-sensitive part of the cell is highly folded - why?
it increases surface area, which allows for more photoreceptor molecules to be present
define sensory receptor proteins
membrane proteins in sensory receptor cells that first detect a stimulus & produce a change in the receptor cell’s membrane potential
define receptor potential
a graded change in membrane potential
what are the 2 receptor cell types?
ionotropic
metabotropic
what characterizes an ionotropic receptor cell?
it has a receptor protein that is a stimulus-gated Na+ channel
what characterizes a metabotropic receptor cell?
it has a receptor protein that activates a G protein
define mechanoreceptors
are they usually ionotropic or metabotropic?
cells that respond to mechanical distortion of their cell membrane
usually ionotropic
define thermoreceptors
are they usually ionotropic or metabotropic?
cells that detect heat & cold
usually ionotropic
define chemoreceptors
are they usually ionotropic or metabotropic?
cells that respond to a presence or absence of specific chemicals
usually metabotropic
define olfaction
a sense of smell
auditory senses work via…
alternating high and low sound pressure waves
define the cochlea
a coiled, fluid-filled tube where sound energy is transduced to electric signals
define the basilar membrane
a membrane in the human inner ear that flexes in response to sound waves and activates hair cells
T or F: the basilar membrane flexes at the same location in response to both high and low pitches of sound
false - the membrane flexes at different locations depending on the pitch of sound
simple visual systems can…
sense and respond to light
more complex visual systems can…
see more detailed images of the environment
define photoreceptors
sensory receptor cells that are light sensitive
define the pupil of the human eye
where light enters the light-sensing part of the eye
what are the 4 steps of light processing in the human eye
light comes into eye through neurons
light is absorbed by rods & cones
info from rods and cones is processed in nuclei
info meets on ganglion cells, which send action potential to brain
rods are…
specialized neurons - photoreceptor cells
cones are…
specialized neurons - photoreceptor cells that allow color vision
rods & cones don’t produce action potentials - what do they do instead?
make graded membrane potentials
define compound eyes
what animals are they found in?
eyes composed of many individual optical units called ommatidia
found in arthropods
what do bats use to find prey?
sound echoes (sonar) for navigation
how to bats use sonar?
their larynx (voice box) makes high-frequency sound waves that bounce off surfaces
bats have specialized _____ for sensing high-frequency sound waves
basilar membranes
what is a lateral line system?
who is it found in?
a sensory organ that detects changes in pressure and movement in water
found in fish and amphibians
olfactory sensory receptors can sense odorants that bind to receptors on what?
chemosensitive hairs that project into mucus
action potentials produced in response to binding of odorants to membrane receptors are sent to where?
olfactory interneurons
what is the purpose olfactory interneurons?
they integrate odorant info received by receptors before sending it to the brain
what are taste buds?
clusters of chemosensory receptor cells
define centralization of the nervous system
the tendency for neurons to be clustered into centralized, integrating organs
define the brain (nervous system)
the largest part of the CNS with the most neurons
give two examples of animals with simple nercous systems
sea anemone, sea star
give 4 examples of animals with more complex nervous systems
flatworm, squid (mollusk), earthworm, humans
what defines a complex nervous system?
having both a central and peripheral nervous system
another name for the autonomic nervous system is…
involuntary nervous system
define autonomic (internal effectors)
effectors controlled by the ANS & not skeletal muscle
what are the 3 divisions of the autonomic nervous system?
enteric, sympathetic, parasympathetic
where is the enteric ANS found?
inside gut wall
where is the sympathetic ANS found?
connected to the CNS via the thoracic and lumbar spinal nerves
where is the parasympathetic ANS found?
connected to the CNS via cranial and sacral nerves
define ganglion
a discrete, anatomically clustered set of neuron cell bodies in the PNS
what is the function of the sympathetic ANS?
immediate response (fight or flight)
what is the function of the parasympathetic ANS?
reaction in more restful situations (rest & digest)
do spinal reflexes come from the brain or the spine?
spine
how do spinal reflexes work?
there is initiation of motor neuronal signals in response to sensory neuronal signals in the spinal cord
define binocular vision
having 2 eyes that show overlapping visual fields
define the optic chiasm
place where 2 optic nerves meet
where is the cerebral cortex located in the brain
outermost layer of the cerebral hemishperes
what is the cerebral cortex made of (cell-wise)?
a thin layer of cell bodies ~4 mm thick
what regions of the brain is the forebrain comprised of?
cerebrum, thalamus, and hypothalamus
what regions of the brain is the hindbrain comprised of?
pons, medulla, & cerebellum
increasing body wait is typically associated with _____ (increasing/decreasing) brain weight
increasing
why does a fish have a small cerebellum?
it is mostly used for olfactory sense
what 3 functions does a mammal use its large cerebellum for?
memory, reasoning, and processing of sensory & motor functions
define the amygdala
brain center responsible for emotion & memory of fear
what is the purpose of skeletal muscle?
provides power for locomotion
define contraction (in muscle)
development of a force
what is sliding-filament theory?
during contraction, small filaments in cells seem to slide past each other
muscle fiber is another term for…
a muscle cell
define actin
a contractile protein in muscle fiber (along with myosin)
define actin & myosin filaments
thin, organized molecules of actin or myosin
define myosin (muscle)
a contractile protein in muscle fiber (along with actin)
define myofibrils
long, longitudinally oriented internal components of a muscle fiber
what are myofibrils made of?
actin and myosin
define a sarcomere
a contractile unit of muscle cells - repeating units of myofibril
define titin
molecules of a protein that hold together thick myosin filaments
what is the purpose of titin?
it holds myosin together and returns sarcomeres to their shorter length after they get stretched
what is tropomyosin & what are its 3 functions?
a protein that twists around each actin chain, controls interactions between actin & myosin, and blocks/unblocks myosin-binding sites
what is troponin & what are its 2 functions?
protein molecules that are attached to tropomyosin. they help control position of tropomyosin and have a role in controlling interactions of actin & myosin
what are cross-bridges?
bridge-like links between actin and myosin filaments connected by myosin heads
what does innervate mean?
to provide neural input
define a neuromuscular junction
a synapse where a motor neuron axon makes contact with a muscle fiber
what is excitation?
when a nerve impulse arrives at a neuromuscular junction & initiates an action potential
what is excitation-contraction coupling?
a process where electrical excitation of a membrane leads to contractile activity by proteins
define a sarcoplasmic reticulum
an endoplasmic reticulum of a muscle cell used for Ca2+ storage and release
define endoskeleton
skeleton inside other tissues (humans - skin)
define exoskeleton
a skeleton that encases the rest of the body
what is bone made of?
an extracellular matrix of collagen protein fibers with insoluble calcium phosphate crystals among them
define cartilage
a flexible skeletal tissue that allows for flexibility
define joints
places where bone and muscles work together
define tendons
flexible connective tissue that attaches muscle and bone
define an antagonistic pair
two muscles that work together in opposite actions - one contracts & the other relaxes
why are antagonistic pairs necessary?
because muscles can only contract & relax in one direction
where are the muscles for swimming located in a fish?
in the middle of its body (not the tail)
what are two types of muscle cells in fish?
slow oxidative cells and fast glycolytic cells
what are slow oxidative cells?
red slow-twitch cells
what are fast glycolytic cells?
white fast-twitch cells
what is a hydrostatic skeleton
when a part of/whole body can become stiff like a skeleton due to high fluid pressure inside
define power of muscle cells
the rate at which work is done
define an oxidative system
system where the citric acid cycle and electron transport is conducted
define a glycolytic system
system that uses anaerobic glycolysis to produce ATP
define an immediate system
a system that uses preformed ATP in cells when contraction begins
the speed of contraction is ____ (fast/slow) in fast muscle fiber and ____ (fast/slow) in slow muscle fiber
fast, slow
the force of contraction is ____ (weak/powerful) in fast muscle fiber and ____ (weak/powerful) in slow muscle fiber
weak, powerful
the length of contraction is ____ (brief/sustained) in fast muscle fiber and ____ (brief/sustained) in slow muscle fiber
brief, sustained
in fast muscle fiber, sarcomeres can have what kind of contraction?
either no contraction or complete contraction
in slow muscle fiber, sarcomeres can have what kind of contraction?
partial contraction is possible
what is the source of ATP in fast muscle fiber?
fermentation
what is the source of ATP in slow muscle fiber?
aerobic respiration
what is an example of a muscle with fast muscle fibers (humans)?
quadricep muscle
what is an example of a muscle with slow muscle fibers (humans)?
the gluteus maximus
