Test 4

Question 1

What are the functions of the nervous system ?

Answer 1

1. Maintaining homeostasis: the cells in the body must work together to maintain homeostasis
2. Receiving sensory input : sensory receptors monitor numerous external & internal stimuli. Sensations from stimuli include all 5 senses
3. Integrating information: the brain & spinal cord are the major organs for processing sensory input & initiating responses.
4. Controlling muscles and glands: skeletal muscles normally contract only when stimulated by the nervous system, thus the NS controls major movement of body
5. Establishing & maintaining mental activity: the brain is the canter of mental activities, including consciousness, thinking, memory and emotions.

Question 2

What are the divisions of the nervous system?

Answer 2

Components which are the: brain, spinal cord, nerves, sensory receptors

And the subdivisions which are:
- Central nervous system ( brain, spinal cord)

• peripheral nervous system: sensory receptors and nerves

Question 3

What are the cranial nerves?

Answer 3

They originate from the brain, 12 pairs

Question 4

What are spinal nerves ?

Answer 4

Originate from the spinal cord, 31 pairs

Question 5

What is ganglion?

Answer 5

Collection of Neuton cell bodies outside CNS

Question 6

What are sensory receptors ?

Answer 6

The ending of neurons or separate, specialized cells that detect temperature, pain, touch , pressure, light , sound and odours

Question 7

What is plexus?

Answer 7

Extensive network of axons located outside the CNS

Question 8

Sensory ( AFFERENT):

Answer 8

transmits action potentials from receptors to CNS

Question 9

Motor ( EFFERENT):

Answer 9

Transmits action potentials from CNS to effectors ( muscles, glands )

Question 10

Explain the somatic nervous system:

Answer 10

• from CNS to skeletal muscles
• voluntary
• single neuron system
• synapse : junction of a nerve cell with another cell

Question 11

Explain the autonomic nervous system (ANS) :

Answer 11

• from CNS to smooth, cardiac muscle and certain glands
• subconscious or involuntary control
• two neuron systems: first from the CNS to ganglion, second from ganglion to effector

Question 12

What are the divisions of the autonomic nervous system?

Answer 12

• sympathetic: prepares body for physical activity
• parasympathetic: regulates resting or vegetating functions such as digesting food or emptying of the urinary bladder
• enteric: plexuses within the wall of the digestive tract, can control the digestive tract but still considered part of the ans because of the parasympathetic and sympathetic neurons that contribute

Question 13

Cells of the nervous system

Answer 13

• Neuroglia: suppers and protects neurons

- Neurons or nerve cells: receive stimuli and transmit action potentials

Question 14

What is the organization of the Neuron

Answer 14

• Cell body or soma
• dendrites: input
• axons: output

Question 15

What is the blood brain barrier ?

Answer 15

Protect neurons from toxic substances

Question 16

What is a Schwann cell/ neurolemmocytes?

Answer 16

Wrap around portion of only one axon to form myelin sheath

Question 17

What is a satellite cell?

Answer 17

Surround neuron cell bodies in sensory ganglia, provides support and nutrients

Question 18

What is a myelinated axon?

Answer 18

Myelin protects and insulates axons from one another

Question 19

What is the nodes of ranvier??

Answer 19

• a gap occurring at regular intervals between segments of myelin sheath along a nerve axon.

Question 20

Explain unmylinated axons

Answer 20

• Not wrapped around the axon

- Gray matter

Question 21

List the organization of the nervous tissue

Answer 21

• gray matter: unmylinated axons, cell bodies, dendrites, Neuroglia,
• white matter : myelinated axons, nerve tract propagate action potentials from one area in the CNS to another

In brain: gray is outer cortex as well as inner nuclei, white is deeper

In spinal cord: white is outer, gray deeper

Question 22

What are electrical signals

Answer 22

• cells produce electric signals called action potential
• transfer of info from one part of body to another
• electrical properties result from ionic concentration differences across plasma membrane and permeability of membrane

Question 23

Explain synapse

Answer 23

• junction between two cells

- site where action potentials in one cell cause action potentials in another cell

Question 24

What are the two types of cells in synapse

Answer 24

• pre synaptic

- post synaptic