bio exam 2 (animals)

____ is due to the turbulence caused by the closure of AV valves at the beginning of systole; _______ is caused by the closure of the aortic and pulmonary valves, marking the end of systole.

"lub", "dub"

most cells can only survive between what two temperatures?

0-40 C

when did plants and animals last share a common ancestor with each other?

1.5-1.6 bya

the mechanism is which a bird processes a single volume of air requires ________ - this is why birds require multiple posterior and anterior air sacs. it is also why the trachea of a typical bird is longer and wide than that of similarly sized animals.

2 cycles of inhalations and exhalation

ICF accounts for ___ of an animals' body fluid

67% (majority)

the broad region that corresponds to the length of the thick filaments (myosin) of the myofibrils. note that both actin and myosin exist here but it corresponds to the regions of myosin, not actin.

A band

atrium

A heart chamber that receives blood.

______ is required to end a sustained muscle contraction.

ATP

myosin itself is actually an __________ - in the presence of ATP, the myosin head hydrolyzes ATP to ADP and an inorganic phosphate, which puts the myosin head in high-energy configuration (sometimes called a cocked position)

ATPase

the relationship between blood flow and resistance:

BF=1/resistance (even a small change in diameter can cause a large change of BF)

includes the brain and spinal cord, integrates sensory information in ganglia. it "makes sense" of the things that we perceive.

CNS (central nervous system)

what are the two major divisions in the vertebrate nervous system?

CNS (central nervous system) and PNS (peripheral nervous system)

is CO2 or O2 more easily moved throughout the body?

CO2 (because the partial pressure gradient is always large and CO2 is much more soluble in water than O2)

shield or "buffers" cells from harsh conditions, allowing large multicellular organisms to be able to survive large fluctuations in the environment; the body closely regulates the temp of this so that it does not deviate much if environmental conditions change.

ECF

can be applied to diffusion of gases across a membrane; expresses the rate of diffusion across a membrane in terms of all the factors that influence it.

Fick's law of diffusion

the area in the middle of the sarcomere where there are only thick filaments (myosin)

H zone

the area near the edge of the sarcomere where there are only thin filaments (actin)

I band

cardiac muscle

Involuntary and striated muscle tissue found only in the heart.

in general, oxygen is able to diffuse over distances of up to 0.5mm and still support aerobic metabolism; some animals like sponges, flatworms, and fish larvae are so small that the surface area of their skin is enough to meet their gas transfer requirements.

Krogh's rule

in terms of Fick's equation, birds minimize ________ and maximize ________.

L; P1-P2 (by unidirectional flow - air moves one way rather than 2- and countercurrent flow of air and blood)

the axis of this filaments (myosin)

M line

the concentration of ______ is high outside of the cell and the concentration of K+ is high within the cell.

Na+

_______ concentration will always be much lower in air because it is more soluble in air than in water

O2

______ does NOT react with water, while _____ does.

O2, CO2

relates the liquid flow rate (V) and the total surface area of flow (SA), which ultimately determines the quantity of the liquid that flows (Q); in the velocity of blood flow.

Ohm's Law: Q=V x SA

countercurrent flow most directly optimizes what component of Fick's equation?

P1-P2

a gas will always diffuse from high _____ to low____ but that does not mean that gases will diffuse from high conc to low conc - gases travel down their partial pressure gradients, NOT concentration gradients.

PA

how do you determine the partial pressure of a particular gas?

PA= (% of gas A in air) x (air pressure)

Includes the sensory and motor neurons that connect to the central nervous system. it allows us to perceive information from our environment and respond, such as by motor output - note that "motor output" is a general term that does not necessarily involve movement (ex: motor neurons also cause glands to secrete substances).

PNS (peripheral nervous system)

what is Fick's law of diffusion and what does each variable represent?

Q = DA x (P1-P2)/L Q = rate of dissusion D = diffusion coeff. (varies based on the diffusion substance, the medium it is diffusing in, and the temperature). A = the cross-sectional area of the respiratory membrane (aka the "doors"). P1-P2 = the difference in PA of gas between 2 sides of the membrane. L = the distance over which the gas has to diffuse.

the pattern of blood flow in the chambers of the heart and blood vessels always goes ....

VA-AV-VA-AV

the border of the sarcomere, which is also the axis of the thin filaments (actin); anchors the actin molecules

Z line

in muscle contraction, calcium causes the vesicles in the motor neuron containing a neurotransmitter called __________ to fuse with the presynaptic membrane, causing the release of this neurotransmitter into the synaptic cleft of the neuromuscular junction (the gap between the motor neuron and the muscle) via exocytosis.

acetylcholine (ACh)

the motor (efferent) division of the peripheral nervous system typically has an impact on target organs by releasing 2 neurotransmitters:

acetylcholine and norepinephrine

thin filament; are wound in a helical fashion, like 2 strands of pearls wound around one another.

actin

each muscle fiber contains a bundle of myofibrils, which are composed of 2 types of filaments: (they play a role in cell mobility, amoebid movements, organelle transport, and cell division; can be found in nearly every cell in the body)

actin (thin filament) and myosin (thick filament)

the signal to contract a muscle is considered an __________ because muscle cells are big and the signal has to be able to travel quickly throughout the cell. note that T-tubules help bring the action potential from the outside of the muscle cell to the myofibrils that lie deep inside the muscle cell and that the sarcoplasmic reticulum surrounding the myofibrils releases calcium to initiate muscle contraction.

action potential

the plasma membrane is an ________ because proteins embedded in the cell membrane actively move materials into and out of the cell. (ex: Na/K pump actively pumps Na ions out of the cells and K ions into the cell. this arrangement is essential for neuron signaling.

active barrier

reflexes are .....

adaptive responses

an action potential is an ___________ change in voltage that propagates itself down the axon. this means that an action potential for a single neuron is always the same. (an action potential is NOT a graded response)

all or nothing

2 advantages of multicellularity

allows cells to become highly specialized and protects cells from large changes in the environment

regulation advantage and disadvantage:

allows cells to function independent of environmental conditions but regulation requires energy.

what are the evolutionary advantages of separating the blood into 2 separate circuits using a heart with 4 chambers? (5)

allows oxygenated blood to be delivered at high pressure and velocity, prevents oxygenated and deoxygenated blood from mixing (so the systemic circuit will always receive blood with high oxygen levels), allows blood pressure in one circuit to be different than the other, allows blood flow to be directed where it is most needed, allows organisms to maintain high metabolic rates.

small sacs at the very end of the terminal respiratory bronchioles that increase the surface area of the lung and increase the surface area for absorption; it is through this that the blood becomes oxygenated so that it can deliver oxygen to the rest of the body; the blood also unloads carbon dioxide here that will be exhaled.

alveoli

where does gas exchange primarily occur in mammals?

alveoli

oxygen gases diffuse from ________ to ______ to ________.

alveoli (lungs) to oxygenated blood to body tissues (high to low PA)

the voltage of a cell can be increased (i.e. the cell membrane will become depolarized) by ....

anything that causes positive charge to flow into the cell or anything that causes negative charge to flow out of the cell. (the voltage can also be reduced in the opposite way)

have thick walls with lots of elastin and collagen because they move blood away from the heart and to the organs of the body.

arteries

how to distinguish arteries vs veins

arteries are thicker, with lots of smooth muscle; arteries have round cross-sections, while veins have flattened cross-sections; blood pressure is higher in the arteries than in the veins.

arteries branch into smaller _______, which bring blood to the capillaries. contraction in them plays a major role in determining the resistance in certain blood vessels and therefore distributing blood throughout the body.

arterioles

what are the 9 levels of organization in an animals body?

atom, molecule, macromolecule, organelle, cell, tissue, organ, organ system, organism

the movement of blood through and out of the heart is regulated by several important valves:

atrioventricular (AV) valves (regulate blood flow between the atrium and the ventricle that prevent backflow), aortic valve (where the aorta leaves the left ventricle) and the pulmonary valve (where the pulmonary artery leaves the right ventricle), and the chordae tendinae (heart strings that hold the AV valves in place while the heart is pumping blood)

vertebrates have 2 or more heart chambers, which include at least one ______ and one _______.

atrium; ventricle

the hypothalamus controls the ______ and ______ response.

autonomic and endocrine

In ___________, the impact of acetylcholine depends on whether it acts in the sympathetic or parasympathetic division; in sympathetic, acetylcholine triggers the release of norepinephrine from the adrenal medulla. norepinephrine acts to inhibit the smooth muscle in the intestines and stimulate the heart muscle, producing fight or flight response; in parasympathetic division, acetylcholine has the opposite effect, reducing heart rate and increasing digestion to produce rest-and-digest response.

autonomic nervous system

division of motor (efferent) division; controls involuntary, subconscious responses to external stimuli. these include all of the body's "routine" functions, such as heartbeat, digestion, and maintaining a stable blood pressure and body temperature; controls a variety of smooth muscles including those in the blood vessels, bladder, eyes, gut, airways of the lungs, reproductive organs, etc. it also controls exocrine glands - glands that secrete their products somewhere other than the blood, such as sweat glands. it also controls several endocrine glands - glands that secrete their products in the bloodstream, such as adrenal medulla; can be divided into 2 major divisions: sympathetic division and parasympathetic division.

autonomic nervous system

involves the nervous system.

autonomic response

action potentials have to flow down the axon, from the _________ (where the action potential begins) to the presynaptic terminal. when an action potential fires at one point along the axon, the depolarization of the membrane opens sodium channels in adjacent points. if the depolarization is greater than the threshold potential, an action potential will be fired at the adjacent point. this is how action potentials "move" down the axon.

axon hillock

the conical region of a neuron's axon where it joins the cell body. electrical signals are typically generated in this region.

axon hillock

A typically long extension, or process, of a neuron that carries nerve impulses away from the cell body toward target cells. some carry electrical signals very long distances, so they must be very long (ex: motor neurons)

axons

an animal's metabolic rate at rest, in a comfortable environment, and when the animal has not eaten recently.

basal metabolic rate (bmr)

- a pacemaker (also called the SA node) in the right atrium generates a wave of signals that tells the heart to contract (the heart is autorhythmic - the activation of cells and subsequent contraction occurs automatically). - the signal is delayed for a fraction of a second at the AV node (which lies buried in a fibrous capsule at the base of the atria). - the signal then passes to the AV bundle (aka bundle of His) which connects the atria and the ventricles. - the signal then passes to the heart's apex via bundle branches (long cardiac myocytes whose only job is to act as an "electrical highway" to the apex). - the signal spreads throughout the ventricles, from the apex back up. - the change in voltage triggers a change in voltage in neighboring cells through the Purkinje fibers, causing a contraction.

basic path of electrical activity in heart

how is a 4 chambered heart an example of convergent evolution?

because it arose independently at least twice (in mammals and in birds) to allow them to meet their energetic demands.

why is the small delay of the signal at the AV node important?

because it causes a delay between the contraction of the atria and the contraction of the ventricles, allowing the ventricles to fill up with blood and the AV valves to close before the ventricles contract.

both autonomic and endocrine responses produce....

behavioral responses that control important regulated variables. (ex: shivering, drinking, hunger, sleep, and finding food).

the left atrioventricular valve is also known as the ________; while the right atrioventricular valve is also known as the ________.

bicuspid/mitral valve; tricuspid valve

are widely considered to have the most efficient gas exchange mechanism, and this mechanism differs significantly from the mechanism used by other vertebrates.

birds

- beginning in the left atrium, oxygenated blood flows through the left AV valve to the left ventricle. - from the left ventricle, blood flows through the aortic valve to the aorta. - blood flows from the aorta to the systemic circuit (it is at this point that oxygen is taken out of the blood and carbon dioxide is picked up) - the deoxygenated blood flows from the systemic circuit back to the heart through the superior and inferior venae cavae (blood from the upper part of the body returns via superior and blood from the lower returns via the inferior). - blood from the superior and inferior venae cavae to the right atrium. - blood flows from the right atrium through the right AV valve to the right ventricle. - then the blood flows through the pulmonary valve to the pulmonary artery. - blood flows from the pulmonary artery to the lungs, where it becomes oxygenated and drops off carbon dioxide. - the oxygenated blood flows in the pulmonary vein back to the left atrium of the heart and the cycle continues.

blood flow in mammals (everything from the left atrium to the vena cavae is part of the systemic circuit while everything from the right atrium to the pulmonary veins is part of the pulmonary circuit).

blood in the arteries usually have high oxygen levels because they are carrying blood to the organs in the body. what is the exception?

blood flowing through the pulmonary artery, which leads from the heart to lungs.

why is the left side of the human heart thicker?

blood on the left side of the heart has to be pumped to the rest of the body, whereas blood on the right side only has to be pumped to the lungs. to pump blood farther, the left side of the heart must be thicker

how do blood plasma and interstitial fluid in the ECF differ?

blood plasma has more protein and contains RBCs

refers to the hydrostatic force exerted by the blood on the vessel walls. it is higher in the arteries than in the veins; is dependent on the pumping of the heart (cardiac output) and on peripheral resistance (the resistance that must be overcome to push the blood through the circulatory system).

blood pressure

what happens to metabolic activity in poikilotherms as environmental temperature increases?

body temp increases and metabolic activity increases because the enzymes involved in metabolic reactions work better at higher temoeratures.

carbon dioxide flows from _______ to _______ to ________.

body tissues to bloodstream to alveoli (high to low PA)

a more complex organization of neurons that is the primary information-processing center in sophisticated organisms, such as squid and humans.

brain

the ___________ is the tissue that needs oxygen the most; without a relatively continuous supply of oxygen, you will suffer from ____ damage and eventually death.

brain

the movement of a fluid driven by pressure

bulk flow

describe how oxygen transport alternates between bulk flow and diffusion:

bulk flow (breathe air in), diffusion (air diffuses across surface of respiratory organs to bloodstream), bulk flow (heart pumps blood to rest of the body), diffusion (oxygen diffuses out of RBCs and into the cells that need it).

gas exchange involves what 2 things?

bulk flow and passive diffusion

plays an important role in muscle fiber contraction; their intracellular levels are usually very low, and it acts as a signal to control proteins when it is allowed in the cytosol.

calcium

transports calcium ions back into the sarcoplasmic reticulum, and calcium levels fall. when this occurs, ATP binds to the myosin, causing it to release the actin filament, ending the contraction

calcium ATPase

___________ consist only of one-cell-layer thick endothelium, while veins and arteries are made up of vascular smooth muscle as well as an endothelial layer. the smooth muscle layer allows these vessels to dilate and constrict, giving them the ability to regulate blood flow by changing resistance in the vessels.

capillaries

are small blood vessels that penetrate the body's tissues and consist of a single, porous layer of endothelial cells that allow exchange between the blood and the interstitial fluid; form together in a network of tiny blood vessels called capillary beds - exhibit progressive branching which allows the diameter of the capillaries to be minimized while the total surface area is maximized; in these small blood vessels, gas and nutrients are exchanged between the blood and tissues.

capillaries

because the quantity of blood remains approximately the same in a closed circulatory system, as the cross-sectional area increases, blood flows more slowly. total cross sectional area is greater in the ________ than in the arteries, so blood flow is much slower in the ________ than in the veins or arteries.

capillaries

hemoglobin can also bind to _______ - some of it that makes its way from cells in the peripheral tissues to the blood cells bind directly to hemoglobin; however, most of it reacts with water, forming carbonic acid, which dissociates into protons and bicarbonate ions. those bicarbonate ions then convert back to carbon dioxide in the lungs, where they are released into the alveolar air space.

carbon dioxide

refers to the sequence of events that occur when the heart beats; during a single one, the heart pumps blood out by contracting and then fills back up by relaxing; consists of 2 phases: diastole and systole

cardiac cycle

muscle that forms the contractile walls of the heart, which consist of striated cells that are connected via intercalated discs. these cells are able to generate their own action potentials without input from a neuron (ex:pacemaker cells make the heart beat); is specialized for pumping blood with cells connected to form a hollow space. it has specializations that allow action potentials to spread between the cells.

cardiac muscle

striated and involuntary; not multinucleated the cellular junctions between cardiac myocytes contain intercalated discs that mechanically connect adjacent cells; has gap junctions that allow action potentials to move between adjacent cells. unlike skeletal muscle, it does not fatigue.

cardiac muscle

most bilaterally symmetrical organisms have _________ nervous systems where the nervous tissue is highly concentrated in the head.

cephalized

created by differences in concentration on either side of the membrane. when a substance is higher in concentration outside of the cell than inside, the force points inside the cell and vice versa. the large the difference in concentration on either side of the membrane, the greater the force and the faster the rate of diffusion.

chemical force

the most common form of synaptic signaling; through the release of neurotransmitters from the presynaptic neuron to the postsynaptic neuron (which could be muscle cells or other neurons. (the binding of a neurotransmitter to the receptor protein opens the ligand-gated ion channel, allowing sodium to enter the cell).

chemical synapse

animals are closely related to ___________ - a group of free-living unicellular flagellate eukaryotes that live in colonies; animals shared a common ancestor with them 800 million years ago.

choanoflagellates

fluid that flows in the circulatory system

circulatory fluid

Transports oxygen, waste, nutrients, hormones, heat, etc... around the body; is highly branched and reaches the vast majority of the body; includes circulatory fluid, a pump, and interconnecting tubes; connects each cell in the body to the body's exchange surfaces.

circulatory system

a circulatory system in which blood is confined to vessels and is kept separate from the interstitial fluid, or the fluid around the cells; the ECF components (blood plasma and interstitial) are kept separate; plasma and small molecules leak out of the vessels (usually at the capillaries), join with the interstitial fluid and come in direct contact with the cells; are found in annelids (segmented worms) and vertebrates.

closed circulatory system

an animal is better able to regulate the distribution of blood in its body with this system because high blood pressure (created by the heart) ensures rapid, effective oxygen and nutrient delivery to the tissues - and therefore this system is found in taxa that are large and active; allows specialized cells that transport oxygen, hormones, and nutrients to be kept in the vessels; allow an organism to control the flow of blood to an area of the body by changing the diameter of blood vessels.

closed circulatory system

why do multicellular organisms slow the pace of reproduction and evolution?

complex multicellular organisms cannot reproduce via mitosis (while unicellular organisms can); this presents evolutionary problems because the rate of evolution is determined by the reproductive rate; large complex animals are typically the first to die off when a catastrophic event occurs because they are unable to evolve fast enough to adapt to changes in the environment.

variables that most animals regulate in the ICF and ECF: (5)

conc of energy-rich molecules (glucose and ATP), conc of oxygen, conc of waste products (CO2), conc of water, salt and other electrolytes, and pH.

what are some major consequences of all-or-nothing firing potentials?

conduction of electric impulses along the neuron is non-decremental (no loss of electrical signal as it moves down the axon), conduction of electric impulses is not instantaneous (bc the firing of action potential takes time), its not the size of the action potential that matters, its the frequency of the action potential that conveys the information (they do not have graded responses)

allow their internal environment to be the same as the external environment. this means that they allow their internal environments to change when their external environment changes (ex: snakes and lizards)

conformers (majority of animals)

consist of cells in a secreted extracellular matrix, perform the function of connecting different parts of the body and maintaining structure (ligaments and tendons); includes bones, blood and fat too!

connective tissue

conformers advantage and disadvantage:

conserve energy by not maintaining a constant internal temperature but are more dependent on their environment.

effectors are considered ______ because they are tightly controlled by regulatory systems

controlled systems

in gills, water flows unidirectionally but opposite of blood in the capillaries so that oxygen can be exchanged in a ___________ - the opposite flow of adjacent fluids that maximizes transfer rates. as blood flows opposite of water, it becomes more and more oxygenated; allows fish with gills to extract a significant amount of oxygen from the water; maximizes the transfer of anything between 2 solutions as long as the membrane between them is permeable.

countercurrent exchange

the myosin head binds to the actin, forming a __________. the myosin then releases ADP and an inorganic phosphate, returning the myosin head to its original low energy position. this causes the actin filament to move toward the center of the sarcomere. this is why the filaments slide as the muscle contracts.

cross-bridge

the numerous, short, highly branched extensions of a neuron that convey nerve impulses toward the cell body. there can be hundreds of these per cell body. are very long in sensory neurons

dendrites

the relaxation phase, during which the ventricles relax and the heart fills with blood. as a result, blood pressure is low. atrial contraction occurs at the end of it, as the blood is pumped from the atria to the ventricles.

diastole

in general, there are 2 kinds of synapses, what are they?

electrical and chemical synapses

results from the interaction of charged particles with electrical charges on either side of the membrane. the force focuses on the fact that opposite charges attract and like charges repel rather than differences in concentration (chemical force). the larger the magnitude, the greater the attraction or repulsion.

electrical force

electrical vs chemical synapses

electrical involves two cells touching one another, while two cells connected at a chemical synapse are separated by a small amount of space.

formed by cells that are joined together with gap junctions made of proteins called connexins; these cell junctions allow the cytoplasm if one cell to flow to the cytoplasm of another cell. electrical signals can therefore be directly transmitted between cells when ions flow through the channels in the cytoplasm. while these action potentials occur quickly, they do not allow the complex integration of neural inputs; are incredibly rare in most vertebrates; used by squids to act fast

electrical synapses

neurons have _____ membranes, which allows for transmission of electrical charge

electrically excitable

is determined by a combination of the chemical force and electrical force.

electrochemical driving force (if the chemical force is greater than the electrical, the driving force is in the direction of the chemical force, vice versa).

involves the production of hormones, such as ACTH, growth hormone, FSH/LH, and prolactin.

endocrine response

is predominantly used for prolonged activities, such as growth, development, and reproduction.

endocrine signaling

the lungs begin as an out-pocketing of the __________ - the embryonic tissue that ultimately gives rise to the digestive system; the lung is highly invaginated which increases the surface area over which gases can diffuse.

endoderm

the single-celled layer that lines the lumen of the blood vessels; the site where all exchange takes place between the blood and the surrounding tissues.

endothelium

mammals are ______ (like birds) and they require a lot of oxygen to maintain the levels of cellular respiration necessary.

endotherms

cover the external surface of the body as well as the internal surfaces of organs and some line blood vessels; functions to protect and regulate (sensory functions, nutrient transport and absorption, and secretion of hormones and sweat).

epithelial tissue

4 major types of tissue

epithelial, connective, muscle, nervous

what is an animal? (6)

eukaryotes, multicellular, heterotrophic, use internal digestion, have muscles, exhibit neuronal signaling.

what are two characteristics plants and animals share?

eukaryotic and multicellular

gills are _______ (folded outward) and lungs are ________ (folded inward)

evaginated; invaginated

the sequence of events that converts an action potential to a muscle contraction. - acetylcholine is released from a motor neuron's axon terminal buds. - acetylcholine binds to receptors on the sarcolemma of the muscle cell. - an action potential is generated, and it travels down the T-tubule. - the action potential opens a calcium release channel in the sarcoplasmic reticulum, releasing calcium onto the myofibrils. - calcium binds to troponin, moving tropomyosin away from the myosin binding sites on actin. cross-bridges form between actin and myosin. eventually, the acetylcholine will be removed from the synaptic cleft. (acetylcholinesterase - an enzyme that degrades acetylcholine). when this occurs, calcium will be transported back to the sarcoplasmic reticulum via active transport, tropomyosin will once again block the myosin binding site, and the cross-bridges will detach.

excitation-contraction coupling

depolarizes the postsynaptic membrane, causing an excitatory postsynaptic potential (EPSP). if the depolarization reaches the threshold, it will elicit an all or nothing action potential.

excitatory response

we can classify synapses based on the effect they have on the postsynaptic membrane: (2)

excitatory synapse and inhibitory synapse

respiratory organs have structures that maximize surface area to increase the rate of diffusion, what are 4 of these structures?

external gills, internal gills, trachea (used by insects) and lungs

what kind of circulatory system do mammals and birds have?

four chambered hearts with two circuits

when neurons are organized into clusters that are able to process information; more centralized arrangement than nerve nets.

ganglia

join cells together by mechanical attachment and protein channels, forming an electrical connection that allows action potentials to directly spread from one myocyte to the next; help a contraction spread throughout the heart in a wavelike fashion.

gap junctions

the uptake of oxygen from the environment and discharge of carbon dioxide into the environment.

gas exchange (respiratory exchange/respiration)

all _______ is done by diffusion down a partial pressure gradient.

gas loading and off-loading

fish have a simple two-chambered heart with one atrium, one ventricle, and two types of capillary beds: the ________ and the ________. therefore, the blood is pumped to the gills and then to the other tissues in a series, meaning that the blood goes straight from the gills to the rest of the body without returning to the heart; fish only have one distinct circuit - blood only has to flow through the heart one time per cycle throughout the body. the oxygen depleted blood eventually travels back to the heart so it can again be pumped to the gill capillaries to gather oxygen.

gill capillaries and systemic capillaries

thin projections on the gill that aid in respiration and excretion and are made of individual "steps" called llamelae which contain capillaries.

gill filaments

gills are made up if a series of ______ and _______ , which are designed to maximize the surface area contact of the fish's circulatory system with the water that flows through the gills.

gill filaments and lamellae

are highly convoluted to maximize their surface area; use muscles to gulp water in and force it over them; use this suction to capture prey as well; oxygen concentration in water is very low, so aquatic animals much increase contact between their respiratory medium and the respiratory surface - they do so by ventilation.

gills

gas exchange mechanisms are made up of respiratory surfaces such as _______ and associated mechanisms that _________ and ________ those surfaces.

gills and lungs; ventilate; perfuse

support, nourish, and insulate neurons; they support the neurons' metabolism, electrically insulate axons, and provide an immune function by cleaning up dead neurons. these include astrocytes, microglia, satellite cells, Schwann cells, and oligodendrocytes; makeup about half of the brain and outnumber neurons.

glial cells

..... are also moved into and out of the cell through the cell membrane (3)

glucose, hormones and amino acids

when the response of the membrane potential is proportional to the strength of the stimulus.

graded response

pumping organ

heart

ventricle

heart chamber that pumps blood out of the heart.

molecule that uses copper rather than iron, which makes their blood blue rather than red; most vertebrates use hemoglobin to carry oxygen to their blood.

hemocyanin

a molecule in vertebrates that dramatically increases the blood's ability to carry oxygen to the tissues. binds reversibly to oxygen; it picks up oxygen from the lungs, transports oxygen to the target tissues in the blood, and then releases oxygen to the cells of the target tissue.

hemoglobin

the urgency to breathe that you feel when you hold your breath results from sensors around your blood vessels that detects .....

high CO2 levels (not low O2 levels)

an animal that maintains a constant internal body body temperature (mammals and birds).

homeotherm

is the metabolic rate higher in homeotherms or poikilotherms?

homeotherms (are energetically expensive)

what would happen if human blood did not contain hemoglobin?

humans would deliver far less oxygen to the tissues

open circulatory systems create a _______ as the fluid pushes against the outer body.

hydrostatic pressure

a region of the forebrain that coordinates both the autonomic nervous system and hormonal regulation via the pituitary gland; is involved in temperature regulation in humans. when the core temperature deviates from a set point of about 37 C, temperature-sensitive cells in it set in motion mechanisms to control the body's temperature.

hypothalamus

describe the basic process of air flow through a bird's respiratory system

inhales (air from environment flows through trachea and into posterior air sacs), exhales (causes air to move from posterior air sacs to the parabronchi of the lungs - where gas exchange takes place), inhales (moves air from lungs to its anterior air sacs), exhales (moves air from anterior air sacs out of the body through the trachea)

summation (spatial and temporal) can also have an _________ effect. for example, if one synapse receives an EPSP while another one receives IPSP, their effects can negate each other.

inhibitory

hyperpolarizes the post-synaptic neuron, causing an inhibitory postsynaptic potential (IPSP). this brings the cell farther away from the threshold, decreasing the probability of an action potential.

inhibitory response

the majority of the ECF is _______.

interstitial fluid

the ECF includes what ?

interstitial fluid (clear fluid around cells - not blood) and blood plasma/intravascular fluid)

oxygen diffuses ....; while carbon dioxide diffuses....

into tissues; into alveoli (lungs)

smooth muscle

involuntary muscle found in internal organs; lines hollow organs and tubes in the body.

open upon the binding of a chemical messenger called a ligand; these channels are most important for the transmission of an electrical signal between cells.

ligand-gated channels

dendrites generally only have _________ channels, while axons generally only have ________ channels

ligand-gated; voltage-gated

invaginated respiratory surfaces of terrestrial vertebrates, land snails, and spiders that connect to the atmosphere by narrow tubes; they are localized so they can only transport oxygen to the rest of the body through a circulatory system; are dead-end sacs in most animals, with the exception of birds.

lungs

describe the efficiency of the lungs in terms of Fick's equation

lungs are surrounded by thin capillaries (reducing L - promotes the diffusion of O2 and CO2); the alveoli have a large cumulative surface area (increasing A - size of tennis court).

maintaining a stable fluid environment is important for ....

maintaining structure, delaying entropy, and allowing cell specialization

takes in air through the nose or mouth to the nasal cavity or oral cavity. from there, the air goes to the pharynx (back of the throat). the esophagus takes food to the stomach, and the trachea takes air to the lungs. the air enters the trachea at the larynx (voicebox). the trachea then divides into 2 bronchi (one for each lung) and air flows from the primary bronchi to the terminal bronchioles. at the end of the respiratory bronchioles are alveolar ducts, which contain alveolar sacs that are made up of alveoli.

mammalian respiration

what are features that gas exchange systems use to maximize the rate of diffusion? (5)

maximizing the diffusion coefficient (is determined by the chemical nature of the resp medium and temperature), increasing the surface area of the respiratory surface (A), maximizing the partial pressure difference (through ventilation and perfusion), minimizing the diffusion path length (L), and countercurrent flow

the voltage across a plasma membrane

membrane potential

what happens to metabolic activity in homeotherms as environmental temperature increases?

metabolic activity increases (while body temp stays constant) in colder or warmer temperatures because the body has to compensate for the temperature difference; flat period is the thermoneutral zone.

the rate at which an organism consumes energy, converting the energy in chemical bonds into heat; influences an animal's demand for food, water, breathing, circulation, waste excretion, and other physiological functions.

metabolic rate

the circulation in the smallest blood vessels - the arterioles, capillaries and venules.

microcirculation

includes motor neurons and takes impulses from the CNS to glands and muscles; the motor division can be divided into 2: somatic nervous system (voluntary) and autonomic nervous system (involuntary).

motor (efferent) division

the acetycholine molecules bind to ligand-gated channels on the ____________ (on the muscle's plasma membrane), allowing Na to enter the muscle. This triggers a strong excitatory postsynaptic potential along the membrane. if the threshold voltage is reached, voltage-gated sodium channels initiate an action potential that travels down _________ and triggers the release of calcium ions from the sarcoplasmic reticulum, which is wrapped around the myofibrils. calcium then binds to troponin and triggers muscle contraction.

motor end plate; T-tubules

consists of a neuron and all the muscle cells that it innervates

motor unit

have an intracellular space, an extracellular space, and an external space.

multicellular organism

a multinucleated cell; the basic unit of a skeletal muscle, which represents a single cell that results from the fusion of multiple embryonic precursor cells called myoblasts

muscle fiber

an insulating coat of proteins and lipids that wraps around the axons of some neurons; is critical because it acts as an insulator, preserving the electrical change as it flows down the axon. this allows for the rapid transmission of a message over relatively long distances.

myelin sheath

muscle tissue of the heart

myocardium (made of cardiac muscle)

myosin and actin are organized into ____________, which group together to form larger __________.

myofilaments, myofibrils

the contraction of the cardiac muscle is _________, meaning it originates from the heart muscle itself rather than from an outside stimulus.

myogenic

the heart is ______ - it beats by itself; does not need a cue from the nervous system.

myogenic

thick filament; consists of a lomg strand with many myosin heads.

myosin

what state would you expect to find the muscles in the body when the body experiences rigor mortis and gets stiff?

myosin bound to actin after a power stroke

favors structures and behaviors that maximize an organisms' evolutionary fitness; for this reason, there is a close link between animal form and function.

natural selection

are negative or positive feedback systems more common?

negative (because these mechanisms usually need to be turned "off" at some point)

a mechanism of response in which a stimulus initiates reactions that reduce the stimulus; oppose a change by dampening stimulus (ex: sweating and shivering)

negative feedback system

when the cell's interior is less positive than the exterior (Na/K pump), the cell is said to have _________ - is measured by placing one electrode outside the axon and another electrode inside the axon.

negative voltage

what mechanism of breathing do mammals use?

negative-pressure breathing (a breathing system in which air is pulled into the lungs - the filling of the lungs is usually active in that it involves contraction of the muscle while the emptying of the lungs is passive in that it involves the relaxation of the muscle).

nerve vs neuron

nerve consists of the axons of many neurons bound together like wires in a telephone cable. the neuronal fibers that make up a nerve are bundled up with connective tissue.

the simplest kind of neural network which consists of a simple network of neurons, without any central processing unit. these simple nervous systems connect the neurons with one another but do not allow for complex processing and coordination. they also allow these organisms to survive when they've lost a part of their bodies (ex: sea stars)

nerve nets

we coordinate bodily activities using the ____ and _____ - both of which transmit signals to receptor cells using neurons and hormones.

nervous and endocrine system

principal source of integration and communication among the body's organ systems; any reaction or movement we make is generated by it; many diseases are associated with it as well; consists of the brain, spinal cord, and peripheral nerves that extend throughout the body.

nervous system

two types of cells are neurons (produce and conduct electrical signals called nerve impulses) and glial cells (supporting cells) - neurons communicate with one another using chemicals called neurotransmitter.

nervous system

how does the nervous and endocrine system differ?

nervous: nerve acts on specific target, acts rapidly; endocrine: hormone can affect regions all over the body, slow-acting, longer lasting effects.

the muscle fibers point of contact with the nerve cell

neuromuscular junction

the region that separates the axon of a motor neuron from a muscle cell.

neuromuscular junction

name 4 of the cellular specifications that muscle fibers have:

neuromuscular junction, sarcolemma, transverse tubules, and sarcoplasmic reticulum (SR)

a specialized type of cell that transmits electrical information to specific locations in the body; are able to transmit electrical information because their membranes are electrically excitable; electrical signals called action potentials are transmitted within each of them, and are then transmitted from one of these to the other via chemical signals.

neuron

what are the two kinds of signaling in the nervous system?

neuronal and endocrine siganaling

the nervous system consists of ________ and ________ (act as nerve "glue" that supports and nourishes nerve cells.

neurons and glial cells/glia

if a neuron is a motor neuron that connects with a muscle, it will form a _________ with that muscle. if a neuron connects with another neuron, a _______ is formed.

neurotransmitter junction, synapse

insulated areas of the axon are interrupted by these non-insulated areas called _________; in myelinated axons, electrical charge can jump from one node of Ranvier to another, dramatically reducing the time it takes for the signal to move down the axon. this is called __________.

nodes of Ranvier; saltatory conduction

oxygen and carbon dioxide similarities (3)

nonpolar, can pass through membrane, no active transport

in contrast to veins, arteries do not have _____.

one-way valves

veins have ________ that help control the direction of blood flow and prevent it from flowing backward. the blood pressure in veins is very low, so contraction of the skeletal muscle due to body movement must keep the blood flowing.

one-way valves

what are the 2 major types of circulatory systems?

open and closed

are much simpler, have fewer parts, and involve no barrier between the cells and the circulatory fluid; involves less energy expense and exert a lower pressure on internal organs, such as the heart; created hydrostatic pressure as the fluid pushes against the outer body - this can help the organism extend its legs or perform other important functions.

open circulatory system

circulatory system in which fluid called hemolymph bathes the tissues and organs directly, and there is no distinction between the circulating fluid and the interstitial fluid; are more rare; ex: insects, arthropods, and mollusks

open circulatory system

animals are _____, _______ systems. they are highly ordered but they require a constant supply of energy to maintain that order

open, dynamic

anything that includes 2 or more tissue types

organ

animals are _______ - they maintain a relatively constant internal osmotic environment. that is, they regulate their salt concentrations.

osmoregulators

what are the 4 major gases found in the air

oxygen (21%), nitrogen (78%), carbon dioxide (0.04%), and argon (0.93%)

why do humans need mechanisms to control and prevent the unwanted accumulation of fluid in the lungs?

oxygen diffuses over short distances in the alveoli of the lungs

cells that spontaneously generate action potentials and reestablish the heart rhythm (also known as pace). they are found in the SA and AV nodes.

pacemaker cells

long tubes that birds have which use multiple accessory air sacs to keep air constantly moving through the lungs; allows birds to extract more oxygen from the air than in mammals, and it allows them to fly at high altitudes without having to rest.

parabronchi

sub division of the autonomic nervous system; is an inhibiting system that is part of the rest-and-digest response; involves a reduced heart rate, reduced blood flow to the muscles, increased blood flow to the gastrointestinal tract and the liver, and increased resources for growth and tissue repair (you might experience this response if you're calm and have just eaten a large meal).

parasympathetic division

determines the direction in which gas will diffuse

partial pressure

at the molecular level, all oxygen transport is by ______ because the body has no mechanism of actively transporting oxygen.

passive diffusion

involves bringing a blood vessel in contact with a tissue such that blood circulates over the gas exchange surfaces. in vertebrates, respiratory organs are highly perfused because oxygen travels from the respiratory organ to the rest of the body via blood vessels; The passage of fluid to an organ or a tissue

perfusion

animals that are small and thin can exclusively on simple diffusion to get their oxygen and other materials so they do not need a circulatory system. what are examples of these?

placozoans, flatworms, nematode worms,

an animal whose body temperature varies with the environmental/external temperature (snakes and lizards); more common in animals than conformity.

poikilotherm

the stronger the membrane potential, the more _____________ the neuron is. - with respect to -65mV, a membrane potential of -90mV is hyperpolarized (less than resting) - with respect to -65mV, a membrane potential of -50mV is depolarized (more than resting)

polarized

bring a change to its completion by amplifying a stimulus; involves the activation of effectors until a climax event (ex: production of oxytocin in child birth, ejaculation, etc.)

positive feedback system

what mechanism of breathing do amphibians use?

positive-pressure breathing (a breathing system in which air is forced/pushed into the lungs; ex: frog)

evolution cannot engineer anything! it works on ....

pre-existing structures by the process of tinkering

send signals to postsynaptic neurons

presynaptic neurons (a single neuron could be pre and postsynaptic at the same time)

mammals have an even higher metabolic rate than fish or amphibians so they require a four-chambered heart which is completely divided into left and right ventricles and atria, and is a key adaptation for endothermic animals, which have extremely high energy demands; consists of two completely separated, parallel circuits: the _________ (which supplies the lungs) and the __________ (which supplies the rest of the body); four-chambered heart promotes efficient gas exchange and is an example of convergent evolution.

pulmonary and systemic circuit

most arteries carry oxygenated blood and most veins carry deoxygenated blood, however in the __________ , the opposite is true.

pulmonary circuit

whereas most fish only have one circuit in their circulatory system, amphibians and reptiles have two: a ________ (which supplies blood to the skin and lungs) and a _________ (which supplies blood to the other tissues of the body); the separation of the circulatory system into to circuits is a major innovation associated with land-based animals; the evolution of two circuits required the addition of one more chamber which is why amphibians have a 3-chambered heart with two atria and a ventricle that is incompletely divided - therefore some mixing of oxygenated and deoxygenated blood occurs, making it less efficient than other mechanisms.

pulmonary circuit and systemic circuit

a dangerous condition in which fluid accumulates in the lungs, resulting from pneumonia, anaphylaxis, or diseases such as cystic fibrosis.

pulmonary edema

secreted compounds that keep the surfaces of the lungs from sticking together, preventing collapse.

pulmonary surfactants

what are the most common types of blood in nature?

red and blue blood

CO2 reacts with water to produce carbonic acid, which dissociates into bicarbonate and hydrogen ions. This _______ pH in blood, making it for acidic. The body has to maintain a blood pH of around 7.3 and it takes steps to correct ant deviation from this set point.

reduces (so if CO2 is not released, blood becomes for acidic)

provide a simple example of the integration of the CNS and PNS; a rapid, automatic motor response to a stimulus that occurs when afferent axons communicate with efferent axons without processing by the brain (ex: if something quickly approaches your eye you will blink).

reflex

consists of the simple chain of neurons that give rise to reflexes; a receptor detects an external stimulus and sends an action potential down a sensory neuron to the integration center in the spinal cord of the CNS. the integration center may directly connect the sensory neuron to the motor neuron, or it may consist of one or many interneurons. the integration center then sends an action potential down a motor neuron, where it has an impact on an effector. this entire process occurs unconsciously, it bypasses processing by the brain.

reflex arc

the period during which the neuron cannot fire another action potential; the length depends on how quickly it takes to reestablish reseting potential after depolarization.

refractory period

maintain a constant internal environment, even if there are changes in the external environment (only birds and mammals)

regulators

animals use _______ to obtain, process, and integrate information and issue appropriate commands to appropriate systems in order to maintain homeostasis.

regulatory systems

have a separate vessel that allows them to shunt blood from the pulmonary system to the systemic circuit, thereby bypassing the lungs; the pulmonary and systemic circuits connect where the arteries exit the heart, which allows the arterial valves to shunt blood flow away from the lungs temporarily when animals go under water for long periods of time to conserve energy.

reptiles

3 disadvantages of multicellularity

requires complex coordination (needs communication), makes each cell dependent on each other, and slows the pace of reproduction and evolution

"stale air" that lungs always have that is considered dead space because it is low in oxygen content but remains in the lungs and cannot be expelled; is important because it keeps the inside walls of the lungs from sticking to one another.

residual volume (RV)

oxygen and carbon dioxide

respiratory gases

the membrane potential characteristic of a non-conducting excitable cell, with the inside of the cell more negative than the outside; in an average neuron, it is about -65mV

resting potential

when an animal dies, calcium from the extracellular fluid or sarcoplasmic reticulum causes muscle contraction, because the animal is dead, it cannot produce ATP so the cross-bridge cannot detach from their actin sites. as a result, the muscles remain locked and contracted until 15-24 hours after death, when enzymes break down the proteins; is used to determine the time of death.

rigor mortis

the cell membrane of the muscle, which is depolarized to begin a muscle contraction.

sarcolemma

the smallest, fundamental repeating unit of striated muscle, bound by the Z lines; the muscle contractile unit of skeletal muscle.

sarcomere

a specialized muscle endoplasmic reticulum that stores and releases calcium, regulating the calcium concentration in the cytosol of muscle cells; surrounds each of the myofibrils; it is not a complete sheet - it has gaps and channels.

sarcoplasmic reticulum

action potentials are ________ because the all-or-nothing nature of them means that the signal is not diminished as it moves down an axon.

self-regenerating

regulatory systems begin with _____ that detect signals in the environment and process them via signal transduction. regulatory systems then compare information about the external signal to the set point and issue appropriate commands to _________ (muscles and glands) that effect changes in the internal environment.

sensors, effectors

includes somatic and visceral sensory neurons and brings impulses to the CNS from receptors. visceral sensory receptors monitor internal organs, while somatic sensory receptors provide information about position, pressure, touch, pain, and temperature. special sensory receptors provide information about taste, smell, vision, balance, and hearing.

sensory (afferent) division

what are the 2 divisions the PNS is divided into?

sensory (afferent) division and motor (efferent) division

what are the three kinds of information necessary for regulatory systems?

set point (reference point), feedback information (tells the brain what is happening in the system), error signal (occurs when feedback indicates that their is a deviation from the set point)

steps of the signal transduction pathway:

signal --> sensor --> signal transduction --> effectors

in an open circulatory system, blood vessels run into _______, which are tiny openings surrounding the organs of the body that allow for gas exchange. the hemolymph circulates throughout the body due to body movements and squeezing of the ______.

sinuses

responsible for voluntary movements; the trigger for it comes directly from the somatic branch of the efferent nervous system; pulls the bones of the skeleton; is specialized for voluntary, rapid contraction and relaxation. it produces fast responses to nerve stimuli. however, it can also be controlled involuntarily: as in the case of spasms and reflexive actions.

skeletal muscle

voluntary, striated, multinucleated

skeletal muscle

write the hierarchy of muscle terms

skeletal muscle (consists of skeletal muscle fibers), skeletal muscle fibers (consist of many myofibrils), myofibrils (contain myofilaments), myofilaments (include the thick and thin filaments, made of myosin and actin)

what is the major difference between skeletal muscle and other kinds (cardiac and smooth)?

skeletal muscle is controlled by the somatic nervous system while the other kinds are controlled by the autonomic nervous system.

what are the 3 muscle types?

skeletal, cardiac, and smooth

the thick and thin filaments do not change length when the sarcomere shortens. rather, they slide past each other longitudinally, causing and overlap. this causes the region occupied only by the actin (I bands) and the region only occupied by myosin (H zone) to shrink.

sliding-filament model

involuntary non-striated muscle found in the intestinal tract, the walls of small arteries, and the walls of the uterus and the bladder; responsible for peristalsis (wavelike movement of materials along the digestive tract); contraction of it is also involved in controlling blood flow (vasoconstriction and vasodilation), giving birth, and controlling the irises in your eyes; coordinate with one another via gap junctions to contract in sheets as a single unit; uses a myosin-linked mechanism (does not depend on troponin or tropomyosin like skeletal muscle).

smooth muscle

muscle that is responsible for involuntary body activities. this kind of muscle lines the hollow organs, such as the bladder, uterus, arteries, and veins; is responsible for regulating the diameters of small arteries and pushing solids and fluids along the digestive tract; is specialized for involuntary control and efficient use of ATP. it can contract for lengthy periods without fatiguing.

smooth muscle

an active transport system that uses ATP to maintain sodium and potassium gradients in nerve cells. It moves sodium and potassium ions against their concentration gradients - Na is moved outside and K is moved inside. For each ATP that is used, 3 Na ions move outside the cell and 2 K ions move into the cell - this creates a situation in which the cell's interior is less positive than the exterior; the passive movement of Na and K takes place through gated ion channels (not direct diffusion through the membrane).

sodium-potassium pump

part of the neuron that houses the nucleus and other organelles; can be an the end of a group of dendrites or it can be in the middle.

soma (cell body)

In ____________, acetylcholine has only a stimulatory effect on target organs. specifically, acetylcholine causes skeletal muscle tissue to contract.

somatic nervous system

division of motor (efferent) division; controls voluntary responses to external stimuli by controlling skeletal muscle contractions. this division of the nervous system is what allows you to engage in complex voluntary movements. this typically involves acetylcholine.

somatic nervous system

if two EPSPs occur at the same time at different synapses, they may be enough to bring the depolarization above threshold and trigger an action potential.

spatial summation

cardiac and skeletal muscle are both _______ .

straited

skeletal muscle

striated and voluntary

__________ stimulation does not elicit an action potential - only stimulation that reaches the threshold voltage causes an action potential.

sub-threshold

sub division of the autonomic nervous system; is an activating system that is part of the fight or flight response; involves an increased heart rate, increased blood flow to the muscles, decreased blood flow to the gastrointestinal tract and liver, and decreased resources for growth and repair (you might experience this response if you see an angry bear or see your ex boyfriend in public)

sympathetic division

in sense, all neurons communicate with other cells via the _______, the region between a neuron and another neuron, or another cell. in general, there are 2 kinds of them: synaptic cleft and neuromuscular junction

synapse

the narrow gap between the synaptic terminal of an axon and the signal-receiving portion of another neuron or effector cell. neurotransmitters released by synaptic terminals diffuse across this gap, relaying messages to the dendrite or effector.

synapse

The ability of synapses to strengthen or weaken over time, in response to increases or decreases in their activity. repeatedly stimulating neurons strengthens the connections between that neuron and other neurons.

synaptic plasticity

a bulb at the end of an axon in which neurotransmitter molecules are stored until their release.

synaptic terminal

oxygenated blood flows from the left ventricle of the heart to target tissues in the arteries. as the artery gets smaller in diameter, it splits into arterioles, which further split into capillaries. gases and nutrients are exchanged in the capillary beds. the capillaries converge into venules, which finally converge into veins, which carry the deoxygenated blood back to the heart.

systemic circuit

is the contraction phase, during which the AV valves close, the ventricles contract, and the heart pumps blood. as a result, blood pressure is high.

systole

2 variables that humans regulate but most animals do not:

temp and blood pressure (bc most animals are conformers)

if two EPSPs occur at the same place on the postsynaptic membrane in rapid succession, they may be enough to bring the depolarization above threshold and trigger an action potential.

temporal summation

what are the 2 ways that postsynaptic neurons perform calculations?

temporal summation and spatial summation

neurotransmitters only _______ bind to ligand-gated channels on the postsynaptic membrane. when they detach, they can be enzymatically degraded or they can be taken back up by the presynaptic neuron.

temporarily

strong connective tissues that connect muscle to bone; transmit the force of a muscle contraction to bones.

tendons

if Na+ flows into the cell.....

the cell's voltage will increase (more positive) and the membrane will become become depolarized (more positive/above resting potential of -65mV)

what are the 3 basic components of a true circulatory system?

the circulatory fluid (i.e. blood), a set of interconnecting tubes or conduits (blood vessels), and a muscular pump (i.e. heart)

the speed of an action potential traveling down an axon is influenced by what 2 things? (are both solutions to the need for rapid transmission of electrical signals)

the diameter of the axon (larger diameter = faster signal is conducted because resistance to current flow decreases as diameter increases) and whether or not the axon is myelinated (myelin sheaths are comprised of glial cells - schwann cells in PNS and oligedendrocytes in the CNS; promote the rapid transmission of information)

a sheet of skeletal muscle on the bottom of the thoracic cavity - contracts, causing the floor of it to drop and the ribcage to rise (the intercostal muscles also contract, causing the ribcage to expand) this creates negative pressure, which sucks air in. to exhale, it is relaxed, the lungs and the thoracic cage recoil, and CO2 rich air goes out.

the diaphragm

what determines whether a neuron will fire an action potential?

the number and composition of synapses

by moving fluids of different solute concentrations in opposite directions, a concentration gradient is set up that lets solutes naturally and passively diffuse from one solution to another, with little energy cost.

the power of counter current exchange

although ______ is efficient for smaller insects, it is not very efficient for larger ones because the trachea have to extend to every cell in the body - which is why we dont see human-sized insects.

the tracheal system

holds that single-celled protists grouped together in a colony, forming a hollow sphere that formed a new space, the extracellular space, on the inside. eventually, certain cells began to specialize certain functions; and the colony of cells later folded in on itself to form specialized tissues.

theory of the evolution of multicellularity

the temperature range over which organisms can function without stress.

thermoneutral zone

does not keep the body's temperature absolutely constant, rather it fluctuates in a narrow band around a set point.

thermoregulation

the process whereby organisms control their inner body temperatures within the optimal range, regardless of the environmental temperatures; is critical because most enzymes function the best over a relatively small range of temperatures.

thermoregulation

why can alligators go years without eating?

they are conformers so they conserve energy.

to control the flow of blood to certain capillary beds based on its current needs....

they can change the diameter of the blood vessels leading to the target tissues via contraction or relaxation of smooth muscle in those vessels (this allows the blood to be diverted to other lower-resistance vessels, which receive higher blood flow as a result).

what kind of circulatory system do amphibians and reptiles have?

three-chambered hearts and two circuits

while birds use unidirectional breathing, mammals use ______ - in which air enters and exits via the same passageway. mammalian gas exchange mechanisms are highly complex, with elaborate lung structures that have features that increase diffusion.

tidal air flow

gas exchange is less efficient in animals that use ________ than in other animals, such as fish. however, there is far more oxygen in the air than in the water so it does not matter.

tidal ventilation

used by most air-breathing vertebrates (including amphibians, reptiles, and mammals), in which they breathe in and out by the same path.

tidal ventilation

evolution operates on pre-existing structures, processes and pathways through __________, moreover, mechanisms are rarely optimal and usually involve compromises and trade-offs.

tinkering

a group of cells that live and work together for a common function

tissue

a regulatory protein that is very elastic and - as its name suggests - very large; it is the largest protein in the body. it helps anchor the thick myosin filament to the Z line at the end of the sarcomere; allows muscles to stretch out and recoil without damaging tissue.

titin

what is the ultimate goal of the circulatory system?

to achieve perfusion (blood flow) through the tissue or organ

what is the purpose of a respiratory system?

to get oxygen into the body and carbon dioxide out

what are the 3 specialized respiratory organs?

tracheae, gills, and lungs

gas exchange systems that infiltrate the body and carry oxygen directly to the cells of insects; these involve essentially elaborate open ducts that get air to the cells of insects; no circulatory system is associated with it; the circulatory system in insects - which is open - is for nutrient and metabolic waste transport, not gas exchange.

tracheal system (tracheae)

infoldings of the plasma membrane of skeletal muscle cells, through which a change in voltage travels from the neuromuscular junction to the sarcoplasmic reticulum.

transverse tubules

a regulatory protein that blocks myosin-binding sites on actin. the contraction of muscle requires those myosin-binding sites to be unblocked .

tropomyosin

controls the position of the tropomyosin to the thin filament. when calcium is present, it binds to it's calcium-binding sites - this changes the location of the tropomyosin such that the myosin-binding sites are uncovered. the myosin heads then attach to the actin, forming a cross-bridge. a power stroke occurs and the cross-bridge bends, pulling the thin filament in toward the M line. the cross-bridge then detaches and returns to the original conformation. another cross-bridge can then form more distally down the actin molecules, and the cycle repeats

troponin

what kind of circulatory system do fish have?

two chambered hearts and a single circuit

are open all the times and typically result in a slight net outflow of potassium from the cell. potassium is in higher concentration inside the cell than outside the cell, so the chemical force is directed outside the cell.

ungated potassium leak channels

what are the 3 kinds of ion channels responsible for electrical signaling?

ungated potassium leak channels, voltage-gated potassium channels, and voltage-gated sodium channels

have an intracellular space and external space (ex: paramecia); they regulate their internal environments but do so across a single membrane.

unicellular organism

whereas mammals use tidal ventilation (breathing in and out), birds have _________ (means that all of the air which comes into contact with the parabronchi is oxygenated) - which is made possible by several air sacs. the air sacs do not facilitate gas exchange, rather gas exchange occurs at the parabronchi, which are surrounded by blood capillaries.

unidirectional air flow

muscle cells are specialized cells that are _______ to animals.

unique

occurs when the one-way valves do not work and blood pools in the veins.

varicose veins

______ occurs when a blood vessel constricts, increasing blood pressure. ______ occurs when a blood vessel dilates, decreasing blood pressure.

vasoconstriction; vasodilation

carry blood to heart and also act as a "blood reservior" which stores blood for times of need.

veins

is controlled by the cross-sectional area of the vessels in which the blood is flowing.

velocity of the blood

involves bringing the respiratory medium (water or air) in contact with the respiratory surface (lungs or gills) through bulk flow; is important because the respiratory surface must exchange gases with the respiratory medium; movement of air in and out of the lungs

ventilation

________ maintains a large partial pressure of oxygen outside the body, and _______ ensures that the blood takes oxygen away as soon as it is taken in. therefore, there is a constant flow of oxygen into the body.

ventilation; perfusion

from the capillaries, blood flows to small __________, which converge into large veins. the veins carry the blood back to the heart so they are usually low in oxygen. the exception is the pulmonary vein which brings oxygenated blood from the lungs back to the heart.

venules

a respiratory organ's form and function are highly dependent upon the respiratory medium - particularly its ________ and _________.

viscosity and gas content

the cell membrane has _______ channels, which open and close based on the voltage across the membrane. that is, the electrical potential of the membrane changes the electric potential over the two ends of these proteins, causing their gates to open or close. - the voltage gated Na channels have 2 gates: the first gate (on top) opens quickly when the membrane is depolarized. the second gate (on bottom) closes slowly when the membrane is depolarized. - voltage gated K channels have only 1 gate: which opens slowly when the membrane is depolarized.

voltage-gated

only open when the membrane is depolarized. this results in a net outflow of potassium.

voltage-gated potassium channels,

only open when the membrane is depolarized. this results in a net inflow of sodium.

voltage-gated sodium channels

what are the reasons water is more difficult than breathing in air? (5)

water is denser than air, water is more viscous, oxygen is more soluble in air than in water, oxygen diffuses faster in air than in water, extracting oxygen from water is energetically costly (this explains why there are no truly endothermic animals that breathe water - they cannot use their energy for thermoregulation because they have to use it to acquire oxygen.

what are some examples of trade-offs and tinkering?

wheels, peacock feathers, banana slug (apophallation), human spine, and vestigial structures.

when will diffusion be the greatest based on Fick's Law?

when A (doors) is large, P1-P2 (pressure difference) is large, and L is small.

why cant fish breathe out of water if air is easier to breathe than water?

when a fish is taken out of the water, the lamellae stick together due to the surface tension of the small amount of remaining water that covers them. this dramatically reduces their surface area and prevents the fish from acquiring enough oxygen to live; they can also not ventilate their respiratory organs in the air as they can in water.

when does the metabolic rate increase?

when the animal is active, uncomfortable, or digesting food.

why is myelination important in humans?

without it, the diameter of the axon would need to be much larger to transmit electrical signals at the same speed it does today.