exam 2

Question 1

Endotherm (endothermy, endothermic)

Answer 1

An organism that generates most of its body heat internally through metabolism.

Question 2

Ectotherm (ectothermy, ectothermic)

Answer 2

An organism that relies primarily on external heat sources to regulate body temperature.

Question 3

Thermoregulation

Answer 3

Definition: The process by which an organism maintains its body temperature within a certain range.

Use: Sweating is a form of thermoregulation that cools the body during exercise.

Question 4

Regional Heterothermy

Answer 4

When different parts of the body are maintained at different temperatures.

Question 5

Temporal Heterothermy

Answer 5

Definition: When body temperature varies at different times.
Use: A hummingbird enters temporal heterothermy at night by lowering its body temperature to conserve energy.

Question 6

Thermal Gradient

Answer 6

Definition: A difference in temperature between two areas.
Use: Heat moves from high to low temperature along a thermal gradient.

Question 7

Antifreeze Protein

Answer 7

Definition: Proteins that prevent ice crystal formation in cells.
Use: Antarctic fish produce antifreeze proteins to survive freezing waters.

Question 8

Thermoneutral Zone (TNZ)

Answer 8

Definition: The range of environmental temperatures where metabolic rate is minimal and temperature regulation requires the least energy.

Question 9

Non-Shivering Thermogenesis (Uncoupling of ETCs)

Answer 9

Definition: Heat production without muscle contractions, often through uncoupling proteins in mitochondria that reduce ATP production and release energy as heat.

Question 10

Countercurrent Heat Exchange

Answer 10

Definition: A system where heat is transferred between fluids flowing in opposite directions, conserving heat.

Question 11

Q10

Answer 11

Definition: A value that describes how much a biological rate changes with a 10°C temperature increase.

Question 12

Torpor

Answer 12

Definition: A temporary state of reduced metabolic rate and lowered body temperature to conserve energy

Question 13

all animals produce

Answer 13

produce metabolic heat but ectotherms do not produce enough to significantly warm an animals tissue

Question 14

nervous and endocrine systems

Answer 14

coordinate the activities of an animals tissues and organs

Question 15

all cells

Answer 15

maintain negative membrane potentials

Question 16

membrane potentials =

Answer 16

the voltage across the membrane

Question 17

Nervous system

Answer 17

A rapid communication system that uses electrical and chemical signals to coordinate body activities.

Question 18

Endocrine System

Answer 18

Definition: A slower communication system that uses hormones released into the bloodstream to regulate body functions.

Question 19

Hormone

Answer 19

A chemical messenger released by endocrine glands that travels through the blood to target cells.

Question 20

Neuron

Answer 20

A specialized cell that transmits electrical and chemical signals in the nervous system.

Question 21

Synapse

Answer 21

The junction between two neurons (or a neuron and another cell) where communication occurs.

Question 22

Dendrite

Answer 22

Definition: The branched part of a neuron that receives incoming signals.
Use: Dendrites receive signals from other neurons.

Question 23

Cell Body

Answer 23

Definition: The main part of the neuron that contains the nucleus and integrates incoming signals.

Question 24

Axon

Answer 24

Definition: A long projection of a neuron that conducts electrical impulses away from the cell body.
Use: The axon carries the action potential toward the next neuron.

Question 25

Neurotransmitter

Answer 25

A chemical messenger released from a neuron that crosses a synapse to affect another cell.

Question 26

Sensory Neuron

Answer 26

A neuron that carries information from sensory receptors to the central nervous system (CNS).

Question 27

Motor Neuron

Answer 27

A neuron that carries signals from the CNS to muscles or glands. Use: A motor neuron causes your arm muscles to contract.

Question 28

Interneuron

Answer 28

A neuron located in the CNS that connects sensory and motor neurons. Use: An interneuron processes information during a reflex.

Question 29

Glia (Glial cells )

Answer 29

Definition: Support cells in the nervous system that protect, nourish, and insulate neurons. Use: Glial cells form myelin around axons.

Question 30

Membrane Potential

Answer 30

The electrical charge difference across a cell membrane. Use: A resting neuron has a membrane potential of about –70 mV.

Question 31

Hyperpolarization

Answer 31

Definition: An increase in membrane potential (inside becomes more negative than resting). Use: After an action potential, hyperpolarization occurs as potassium exits the cell.

Question 32

Depolarization

Answer 32

A decrease in membrane potential (inside becomes less negative). Use: During depolarization, sodium ions enter the neuron.

Question 33

Myelin

Answer 33

A fatty insulating layer around axons that increases signal speed. Use: Myelin allows faster transmission of electrical signals.

Question 34

Saltatory Conduction

Answer 34

The process where action potentials “jump” from node to node along a myelinated axon. Use: Saltatory conduction speeds up nerve impulse transmission.

Question 35

Node (Node of Ranvier )

Answer 35

A gap in the myelin sheath where ion channels are concentration Use: Action potentials are regenerated at each node during saltatory conduction.

Question 36

Synapse

Answer 36

Definition: The junction where one neuron communicates with another neuron or target cell. Use: At a synapse, signals are passed either electrically or chemically.

Question 37

Electrical Synapse

Answer 37

A synapse where ions flow directly between cells through gap junctions. Use: Electrical synapses allow very fast communication, such as in escape reflexes.

Question 38

Gap junction

Answer 38

Protien channels that directly cytoplasm

Question 39

Synaptic Plasticity

Answer 39

Definition: The ability of synapses to strengthen or weaken over time. Use: Synaptic plasticity is the cellular basis of learning and memory.

Question 40

Chemical Synapse

Answer 40

Definition: A synapse where neurotransmitters are released into a synaptic cleft to communicate between cells. Use: Most synapses in the human brain are chemical synapses.

Question 41

Synaptic Vesicle

Answer 41

Definition: A membrane-bound sac in the presynaptic neuron that stores neurotransmitters. Use: When an action potential arrives, a synaptic vesicle releases neurotransmitter into the synaptic cleft.

Question 42

Presynaptic

Answer 42

Definition: Refers to the transmitting neuron that releases neurotransmitter. Use: The presynaptic terminal contains vesicles filled with neurotransmitter.

Question 43

Postsynaptic

Answer 43

Definition: Refers to the receiving cell that has receptors for neurotransmitter. Use: The postsynaptic membrane contains receptors that detect chemical signals.

Question 44

Metabotropic Receptor

Answer 44

Definition: A receptor that activates a G-protein and second messenger system instead of directly opening an ion channel. Use: A metabotropic receptor produces a slower but longer-lasting effect.

Question 44

Ionotropic Receptor

Answer 44

Definition: A receptor that directly opens an ion channel when a neurotransmitter binds. Use: An ionotropic receptor produces a rapid response by allowing ions to flow into the cell.

Question 45

Depolarization

Answer 45

Definition: A decrease in membrane potential (inside becomes less negative). Use: Sodium influx causes depolarization of the postsynaptic membrane.

Question 46

Hyperpolarization

Answer 46

Definition: An increase in membrane potential (inside becomes more negative). Use: Potassium leaving the cell can cause hyperpolarization.

Question 47

Excitatory Postsynaptic Potential (EPSP)

Answer 47

Definition: A small depolarization that increases the likelihood of an action potential. Use: An EPSP moves the membrane potential closer to threshold.

Question 48

Inhibitory Postsynaptic Potential (IPSP)

Answer 48

Definition: A small hyperpolarization that decreases the likelihood of an action potential. Use: An IPSP makes it harder for the neuron to reach threshold.

Question 49

Synaptic Integration

Answer 49

Definition: The process by which a neuron sums all incoming EPSPs and IPSPs to determine whether to fire an action potential. Use: During synaptic integration, excitatory and inhibitory signals are combined at the axon hillock.

Question 50

G-Protein Coupled Receptor (GPCR)

Answer 50

Definition: A type of metabotropic receptor that activates a G-protein inside the cell to trigger intracellular signaling pathways. Use: Many neurotransmitters bind to G-protein coupled receptors to produce longer-lasting cellular changes.