Chapter 24: The Nervous System

Question 1

the nervous system

Answer 1

survival of organisms depends on their awareness of the world and their ability to avoid physically harmful situations

Question 2

why do we need a nervous system?

Answer 2

to receive stimuli, process that information, and initiate responses

Question 3

two types of cells in the nervous system are

Answer 3

neurons and glial cells

Question 4

neurons

Answer 4

generates and conducts electrical impulses. groups of them are bundled together into nerves and the parts of them include cell body, dendrites, and axonl

Question 5

types of neurons

Answer 5

sensory, motor, and interneruorns

Question 6

sensory neurons

Answer 6

collect information from an animal’s environment. responses to temperature, touch, taste, smell, light, or sounds

Question 7

motor neurons

Answer 7

initiate animals’ response to stimuli by covering signals to muscles or glands

Question 8

interneurons

Answer 8

interpret signals coming from sensory neurons and relay them to motor neurons. located only in the brain and spinal cord

Question 9

glial cells

Answer 9

support the neurons and contain Schwann cells, oligodendrocytes, and astrocytes (that form blood-brain barrier)

Question 10

myelin sheath

Answer 10

produced by schwann cells in the PNS and oligodendrocytes in the CNS

Question 11

nodes of Ranvier

Answer 11

small area of the axon that is exposed between cells, also essential for transmission of the nerve impulse

Question 12

central nervous system

Answer 12

processes info from sensory cells to send out instructions

Question 13

peripheral nervous system

Answer 13

detects stimuli and transmits signals. sensory pathways(receive info from environment) and motor pathways (sends signals to muscles and glands)

Question 14

somatic

Answer 14

voluntary nervous system and relays signals to skeletal muscles

Question 15

autonomic

Answer 15

involuntary nervous system that relays signals to glass, smooth muscle tissue and cardiac muscle

Question 16

the two components of the autonomic nervous system is

Answer 16

the sympathetic and parasympathetic

Question 17

sympathetic

Answer 17

the body’s fight or flight response during stress. includes increased heart and breathing rates as well as increased blood flow to muscles

Question 18

what does the peripheral nervous system interact with

Answer 18

the central nervous system

Question 19

reflexes

Answer 19

allows organisms to respond fast to immediate danger. signals the motor neuron through the spinal cord

Question 20

how do neurons work?

Answer 20

generation of action potentials

Question 21

neurons are cells and have

Answer 21

plasma membrane that is impermeable to membranes

Question 22

membrane potential

Answer 22

the difference in charge between the inside and outside of the cell. action potential and resting membrane.

Question 23

active transport

Answer 23

requires energy

Question 24

ion channels can respond to the environment by

Answer 24

transmembrane proteins that create channel ions that can diffuse through. can be open, closed, or inactive.

Question 25

if ion channels are closed

Answer 25

its a resting potential and closed

Question 26

if the ion channel is open

Answer 26

then its the response to a nerve impulse and the gate open and Na+ enters the cell

Question 27

if the ion channel is inactive then

Answer 27

the channel does not open in response to a new signal

Question 28

ion pumps

Answer 28

move ions from an area of lower concentration to an area of higher concentration

Question 29

sodium-potassium pump

Answer 29

pumps Na+ out of the cell and K+ into the cell

Question 30

resting membrane potential

Answer 30

membrane potential at rest. -70 mV for most neurons and can result from different Na+ and K+ concentrations inside and outside the cell

Question 31

dendrites receive

Answer 31

external stimuli

Question 32

action potentials

Answer 32

sudden and extreme changes in membrane potential. dendrites collect in the cell body

Question 33

action potential

Answer 33

membrane potentail becomes more positive (+30-40mv)

Question 34

what do voltage-gated Na+ channels do?

Answer 34

they open

Question 35

refractory period

Answer 35

period of time when the Na+ channels cannot reopen

Question 36

what are the 5 steps of action potential formation?

Answer 36

resting potential, threshold potential, peak action potential, repolarization, and hyperpolarization

Question 37

the action potentials moves

Answer 37

down the axon

Question 38

gray matter

Answer 38

mostly cell bodies and dentrites

Question 39

white matter

Answer 39

mostly axons

Question 40

what are the effects when you lack myelin

Answer 40

it can be shown in babies when learning how to walk

Question 41

myelin

Answer 41

gradually last and scar tissue forms. Neurons lose the ability to conduct electrical impulses

Question 42

the______ is the organ through which blood flows to maintain water and solute homeostasis in the body.

Answer 42

kidney

Question 43

freshwater fish are

Answer 43

hypertonic

Question 44

through the process of _______, water and other solutes in filtrate needed by the body are returned to interstitial fluid.

Answer 44

reabsorption

Question 45

what happens to the concentration of filtrate as it moves through the part of the nephron highlighted in red?

Answer 45

the concentration decreases

Question 46

the normal waste product of the urinary system is made of excess water and

Answer 46

urea

Question 47

what are the two types of cells that make up the nervous system?

Answer 47

glial cells and neurons

Question 48

which ion is involved in the firing of an action potential?

Answer 48

sodium ions