DAT bio Chapter 11.4 Nervous system

Question 1

Structure of neuron

Answer 1

has three parts: the soma (cell body),
dendrites (extensions that receive signals), and
the axon (sends signals out).

Question 2

What is the axon hill lock?

Answer 2

Place where the axon connects to the cell body.
Responsible for the
summation of graded potentials.

Question 3

What is myelin sheath?

Answer 3

fatty insulation of the axon
that speeds up action potential propagation by
stopping ion exchange.

Question 4

In the CNS myelin sheath is formed by

Answer 4

oligodendrocytes

Question 5

In the PNC myelin sheath is formed by

Answer 5

schwann cells

Question 6

What are the nodes of ranvier?

Answer 6

• gaps between myelin
  sheaths where ion exchange occurs.
  Propagation of the action potential occurs
  here, jumping from gap to gap (node to node)
  in a process called saltatory conduction.

Question 7

Steps of an action potential

1)

Answer 7

At resting potential, the membrane potential
of the neuron is around -70mV and is
maintained by Na+/K+ ATPases, which pump
three Na+ ions out and two K+
ions in, powered
by hydrolysis of one ATP. K+
leak channels are
also present and help maintain resting
potential through passive K
\+
leakage.

Question 8

Steps of an action potential

2)

Answer 8

When a stimulus causes threshold potential
to be reached (around -55mV in neurons),
voltage-gated Na+ channels open up, letting
Na+
in, resulting in depolarization of the
neuron (reaches a peak of around +30mV to
+40mV).

Question 9

Steps of an action potential

3)

Answer 9

Next is repolarization of the neuron due to
the opening of voltage-gated K+ channels,
letting K+ out. This causes the membrane
potential to become less positive since positive
ions are leaving.

Question 10

Steps of an action potential

4)

Answer 10

When the membrane potential becomes even
more negative than the normal resting
potential, this is known as hyperpolarization.
This results in a refractory period being
established, during which another action
potential cannot be fired because the
membrane potential is very negative.

Question 11

Steps of an action potential

5)

Answer 11

The membrane potential returns to normal
resting potential through the pumping of
Na+/K+ ATPases and K+
leak channels.

Question 12

What is the absolute refractory period?

Answer 12

refers to the
period after the initiation of the action potential
during which another action potential cannot be
fired no matter how powerful the stimulus is. It is
due to the inactivation of voltage-gated Na
+

channels after they open.

Question 13

What is The relative refractory period?

Answer 13

period after the action potential fires during which
a stronger than normal stimulus could cause
another action potential to be fired.

Question 14

What is the synapese?

Answer 14

space between two neurons

Question 15

who sends the signal the presynaptic or postynaptic

Answer 15

presynaptic

Question 16

Steps of synaptic transmission step 1

Answer 16

Action potential reaches the end of the
presynaptic axon, causing voltage gated
calcium channels to open and letting Ca2+
ions into the neuron.

Question 17

Steps of synaptic transmission step 2

Answer 17

The Ca2+ ions cause synaptic vesicles to fuse
and undergo exocytosis, releasing
neurotransmitters into the synapse.

Question 18

Steps of synaptic transmission step 3`

Answer 18

The neurotransmitters (described in the table
on the next page) bind to ligand-gated ion
channels on the postsynaptic neuron,
producing graded potentials (depolarizations
or hyperpolarizations of the membrane).

Question 19

Steps of synaptic transmission step 4

Answer 19

These graded potentials summate at the axon
hillock and an action will fire if the summation
of graded potentials is higher than the
threshold potential of neurons.

Question 20

What is excitatory postsynaptic potential (EPSP)

Answer 20

graded potential that depolarizes the membrane.

Question 21

What does excited neurotransmitter cause in EPSP

Answer 21

cause Na+
ion gates to open and let Na+
ions flow into the cell.

Question 22

What is inhibitory postsynaptic potential (IPSP)

Answer 22

graded potential that hyperpolarizes the

membrane.

Question 23

What does excited neurotransmitter cause in IPSP

Answer 23

Inhibitory neurotransmitters cause K+
ion gates to open and let K+
ions flow out of the
cell. Another IPSP type allows influx of Cl-,
allowing negative Cl-
ions in.

Question 24

What are non neuronal cells in the nervous system that help support and surround neurons?

Answer 24

glial cells

Question 25

Glial cells are divided into

Answer 25

microglial cells and macroglial cells

Question 26

Microglial cells are _______that protect the ______

Answer 26

macrophages | CNS

Question 27

Microglial cells have many subtypes

Answer 27

``` astrocytes schwann cells oligondendrocytes satellite cells ependymal cells ```

Question 28

Astrocytes

Answer 28

the most abundant glial cell and form the blood-brain barrier. They also help recycle neurotransmitters and provide blood supply to the CNS neurons.

Question 29

Schwann cells

Answer 29

form the myelin sheath in the | peripheral nervous system (PNS).

Question 30

Oligodendrocytes

Answer 30

form the myelin sheath in | the central nervous system (CNS).

Question 31

Satellilte cells

Answer 31

same functions as | astrocytes but instead help PNS neurons.

Question 32

Ependymal cells

Answer 32

produce cerebrospinal fluid | (CSF), which cushions the CNS.

Question 33

CNS is composed of

Answer 33

brain and spinal cord

Question 34

PNS is composed of

Answer 34

nerves branching off the CNS

Question 35

In embryonic development we consider ____ ____ ____ in the CNS

Answer 35

forebrain midbrain hindbrain

Question 36

Forebrain develops into two things

Answer 36

telencephalon | diencephalon

Question 37

Telencelphalon gives rise to

Answer 37

cerebrum

Question 38

diencephalon gives rise to

Answer 38

thalamus hypothalamus pineal gland

Question 39

mid brain develops into

Answer 39

mesencephalon

Question 40

mesencephalon gives rise to

Answer 40

midbrain

Question 41

hind brain develops into

Answer 41

metencephalon | myelencephalon

Question 42

metencephalon gives rise to

Answer 42

pons, cerebellum

Question 43

myelencephalon gives rise to

Answer 43

medulla oblongata

Question 44

the developed brain cortex is divided into what four lobes?

Answer 44

frontal lobes temporal lobes occipital lobe parietal lobe

Question 45

frontal lobe function

Answer 45

higher function decision making, problem solving attention memories and emotions

Question 46

temporal lobe functions

Answer 46

speech/language | hearing

Question 47

occipital lobe functoin

Answer 47

vision

Question 48

parietal lobe

Answer 48

``` visual perception (PAT pattern folding) touch/pain/ temp sensation ```

Question 49

Where is the cerebellum located?

Answer 49

underneath the occipital lobe and is responsible for the coordination of movement

Question 50

The autonomic nervous system is divided into what two things

Answer 50

sympathetic and parasympathetic nervous system

Question 51

Sympathetic nervous system is _____

Answer 51

fight or flight

Question 52

Parasympathetic nervous system is _____

Answer 52

rest and digest

Question 53

Sympathetic nervous sytem effects are

Answer 53

Release of sugar into blood for energy. ● Increase in heart rate for oxygen delivery to brain and muscles. ● Dilation of bronchi and bronchioles to allow more oxygen into lungs. ● Dilation of the pupil to give the brain more visual information.

Question 54

Parasympathetic nervous system effects

Answer 54

Relaxation of muscles. ● Decrease in heart rate. ● Maintenance of homeostasis. ● Increase in gastrointestinal activity.

Question 55

what is a ganglion

Answer 55

cluster of nerve bodies | in the peripheral nervous system.

Question 56

The autonomic nervous system’s neurons are either ____ or _____

Answer 56

preganglionic or postganglionic

Question 57

the preganglionic neurons comes from where?

Answer 57

the central nervous system and synapses with the postganglionic neuron at the ganglion.

Question 58

Sympathetic nervous system contains

Answer 58

short preganglionic nerves and long postganglionic nerves

Question 59

Parasympathetic nervous system

Answer 59

long preganglionic nerves and short postganglionic nerves

Question 60

Sympathetic nervous system → uses what

Answer 60

acetylcholine (Ach) for preganglionic nerves and norepinephrine (NE)/epinephrine (E) for postganglionic nerves. The sympathetic nervous system also can stimulate the adrenal medulla to release NE/E into the blood.

Question 61

Parasympathetic nervous system → uses

Answer 61

acetylcholine (Ach) for both preganglionic and | postganglionic nerves.

Question 62

What takes in sound waves

Answer 62

outer eat

Question 63

what transfer the sound from outer ear to middle ear?

Answer 63

tympanic membrane

Question 64

Where is the malleus, incus, and stapes located?

Answer 64

middle ear

Question 65

The middle ear is composed of three bony ossicles. name them

Answer 65

malleus incus stapes

Question 66

The ossicles transfer _____ through the ear and ____ the ____

Answer 66

vibrations middle ear amplify the signal

Question 67

The stapes transfers the vibrations from the middle ear to the inner ear using what

Answer 67

oval window

Question 68

What does the cochlea use to convert mechanical signal into a neuronal signal known as transduction?

Answer 68

uses fluid and hair

Question 69

What is the round window?

Answer 69

membrane covered opening between the middle ear and the inner ear, similar to the oval window. It helps the fluid expand and vibrate.

Question 70

The semicircular canal contains what

Answer 70

fluid and hairs. | gives info about persons movement (reason why we get dizzy)

Question 71

Cornea

Answer 71

transparent; focuses light and | protects the eye.

Question 72

iris

Answer 72

controls the size of the pupil

Question 73

lens

Answer 73

focuses images on retina

Question 74

retina

Answer 74

back of the eye that has photoreceptors (cones and rods)

Question 75

fovea

Answer 75

highest concentration of photoreceptors in the retina and responsible for high acuity vision.

Question 76

Amacrine and bipolar cells do what

Answer 76

take info from rods and cones and transmit that info to ganglion cells of the optic nerve fiber

Question 77

optic nerve

Answer 77

bundle of axons that transmits visual info to the brain

Question 78

optic disk

Answer 78

blind spot of the eye, where the optic nerve passes through to reach the brain

Question 79

Sclera

Answer 79

protective connective tissue that surrounds the eye, the white part of the eye

Question 80

Choroid

Answer 80

vascular connective tissue

Question 81

The tongue has how many taste receptor cells

Answer 81

5

Question 82

Taste info is sent where

Answer 82

thalamus and subsequently the gustatory cortex

Question 83

Nose contains what

Answer 83

olfactory receptor cells

Question 84

What does the olfactory receptor cells sense

Answer 84

molecules and send signals to the olfactory cortex which gives us the perception of smell. These signals also integrate in the thalamus and orbitofrontal cortex for smell sensation.