Ch 8

Question 1

What does the rental nervous system consist of?

Answer 1

Brain and spinal cord

Question 2

What does the brain and spinal cord do? (CNS)

Answer 2

Brain-located within the cranium

Spinal cord- located within the spinal column from the brain to the lumbar vertebrae

It integrates and coordinates the processing of sensory data and the transmission of motor commands.

Question 3

What is the peripheral NS?

Answer 3

Includes all the neural tissue outside the CNS

Consists of two divisions, the afferent(afferens, bringing to) division from the receptors.

The efferent division carries motor commands from the CNS to muscle and glands. Includes the autonomic NS and somatic NS

Question 4

What does the peripheral NS do?

Answer 4

The autonomic NS control system the acts largely unconsciously and regulates bodily functions such as the HR, digestion, Respiratory rate, pupillary response, urination, and sexual arousal.

Question 5

What two types of cells are in near tissue?

Answer 5

Neurons and neuroglia

Question 6

What are neurons?

Answer 6

Neurons are the basic functional units of the nervous system. All neural functions involve the communication of neurons with one another and with other cells.

Question 7

What is the structure of neurons?

Answer 7

Multipolar neurons are the most common type.

A MP neuron has a cell body, several branching, sensitive dendrites which receive incoming signals, and a single long axon, which carries outgoing signals toward one or more axon terminals.

Question 8

What is the neuroglia cells in neural tissue?

Answer 8

Regulate the environment around neurons, provide a supporting framework for neural tissue, and act as phagocytes. Far outnumber neurons.

Question 9

What are clusters of rough endoplasmic reticulum and free ribosomes?

Answer 9

They are known as nissl bodies. They give a gray color to areas containing neon cella bodies and account for the color of gray matter seen in brain and spinal cord dissections.

Question 10

What is another name for electrical impulses?

Answer 10

Action potential that travels along the axon.

Question 11

Where does action potentials begin?

Answer 11

At a thickened region of the cell body called the axon hillock. the axon may branch along its length, producing branches called collaterals.

Question 12

What is a synapse?

Answer 12

A site where a neuron communicates with another cell.

Question 13

What are dendrites?

Answer 13

Dendrites are processes (extensions) that transmit impulses toward the cell body

Question 14

What of a neuron transmits impulses away from the cell body?

Answer 14

The one axon of a neuron

Question 15

In the Peripheral NS, what type of cells are axons and dendrites wrapped in?

Answer 15

Schwann cells

Question 16

What are schwann cells?

Answer 16

Schwann cells grow to surround the axons and dendrites, enclosing them in several layers of schwann cell membrane.

These layers are the myelin sheath; myelin is a phospholipid that electrically insulates neurons.

Question 17

What is the neurolemma?

Answer 17

Wherever a Schwann cell covers an axon, the outer surface of the schwann cell is called the neurilemma.

The nuclei and cytoplasm of the schwann cells are outside the myelin sheath and are called the neurolemma.

There are NO SCHWANN CELLS in the CNS, so regeneration of neurons is not possible

Question 18

What are the nodes of ranvier?

Answer 18

The spaces between adjacent schwann cells

Important for conduction

Question 19

What is an action potential (electrical impulse)?

Answer 19

Propogated change in the membrane potential of excitable cells.

Excitable cells are the only cells that have an electrically excitable membrane tat can be stimulated to propagate action potentials.

Muscle fibers, cardiac muscle cells, and the axons of neurons have excitable membranes.

An action potential in a neuron is also known as a nerve impulse.

Question 20

what is a synapse?

Answer 20

A Synapse is a site where a neuron communicates with another cell.

In the NS, info moves from one location to another in the form of action potential (nerve impulses) along axons.

Consequence of the presence of synapses is that they ensure one-way transmission of impulses

Question 21

Where does a neuron communicate with a muscle cell?

Answer 21

Neuromuscular junction.

Question 22

What are neurotransmitters and an example?

Answer 22

Convert electrical signals to chemical messages at the synapse (where a neuron communicates with another cell)

EX: acetylcholine

Question 23

What are the types of sensory neurons?

Answer 23

Sensory neurons: carry info from the body to the brain

Somatic sensory neurons- from receptors in skin, skeletal muscles, and joints are called somatic sensory neuron.

Visceral sensory neurons- from receptors in internal organs

Question 24

What are the type of motor neurons?

Answer 24

Motor neurons: carry info from the brain and spinal cord to effectors

Somatic motor neurons: linked to skeletal muscle

Visceral motor neurons: linked to glands

Question 25

Types of neurons

Answer 25

Interneurons- found entirely within the CNS

Connect neuron to neurons

Question 26

What is a nerve?

Answer 26

A nerve is a group of axons of many neurons, with blood vessels and connective tissue.

Question 27

How many cranial nerves are there?

Answer 27

12 pairs