Intro to Nervous System and CNS Flashcards Preview

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1

Name the two major divisions of the nervous system and list the structures that comprise each one.

CNS (central nervous system): brain and spinal cord
PNS (peripheral nervous system): cranial nerves, spinal nerves, number of ganglia, specialized sensory receptors

2

Define the ANS in terms of its relationship to the rest of the nervous system and its function.

ANS (autonomic nervous system): contains parts of CNS and PNS that control involuntary muscle tissue and glandular epithelium

3

List the Functions of the CNS

1. Receive the sensory impulses carried by the cranial and spinal nerves
2. Processing and storing information
3. Sending motor impulses to muscle tissue and glandular epithelium tissue

4

List the Functions of the PNS

1. Converting (transducting) various forms of energy to sensory impulses - you need some special sensory receptor cells (photoreceptors, thermoreceptors, chemoreceptors, and mechanoreceptors)

2. Conducting Sensory impulses into CNS via cranial and spinal nerves. Nerves serve as functional extensions of brain and spinal cord.

3. Distributing the motor impulses which originate in brain and spinal cord to muscle tissue and glands of the body. Travel in same cranial and spinal nerves but carried by diff. nerve cells.

5

Systematically represent the three anatomic types of neurons and state the functions of each.

1. Multipolar Neurons: have several dendrites and a single axon (which may have numerous branches)

2. Bipolar neurons: have a single dendrite and a single axon; carry sensory impulses interpreted by CNS as vision, body/balance, audition, and olfaction (smelling)

3. Pseudounipolar neurons: axonal proces fused directly to single dendritic process making direct contact with cell body; carry all sensory info except of that relegated to bipolar neurons

6

Compare the four functional types of neurons in regard to their anatomic type, location of their cell bodies, and the structures that they are motor to or sensory from.

Somatic Efferent (SE)

Anatomic type: multipolar

Cell body location:
- brain - cranial nerve motor nuclei
- spinal cord - anterior gray column

Type/Distribution of Impulses:
- motor to skeletal muscles

7

Compare the four functional types of neurons in regard to their anatomic type, location of their cell bodies, and the structures that they are motor to or sensory from.

Visceral Efferent (VE)

PART OF ANS

Anatomic type: multipolar

Cell body location:
- brain - motor nuclei of cranial nerves 3,7,9,10
- spinal cord - lateral gray column in sacral region, autonomic ganglia

Type/Distribution of Impulses:
- motor to smooth m. ; cardiac m. ; and glandular epithelium

8

Compare the four functional types of neurons in regard to their anatomic type, location of their cell bodies, and the structures that they are motor to or sensory from.

Somatic Afferent (SA)

Anatomic type: Pseudounipolar (some bipolar)

Cell body location: Retina and sensory ganglia of cranial and spinal nerves

Type/Distribution of Impulses:
- sensory from retina (vision), internal ear (audition and balance), skin, skeletal muscle, bones, joints

9

Compare the four functional types of neurons in regard to their anatomic type, location of their cell bodies, and the structures that they are motor to or sensory from.

Visceral Afferent (VA)

Anatomic type: Pseudounipolar (some bipolar)

Cell body location: Nasal mucosa and sensory ganglia of cranial and spinal nerves

Type/Distribution of Impulses: sensory from nasal mucosa (smell), oral mucosa (taste), deep body organs

10

State the function and location of each of the six types of glial cells.

Neurolemmocytes

*note which ones are CNS/PNS

(known as Schwann cells)

-flattened cells that form electrically insulating layers around axons in the PNS called meylin sheaths
- there are myelinated and unmyelinated cells in the PNS

11

State the function and location of each of the six types of glial cells.

Oligodendrocytes

*note which ones are CNS/PNS

cells which form myelin sheaths around axons within the CNS

- contains few dendrites
- can myelinate multiple axons (one cell can do multiple things)

12

State the function and location of each of the six types of glial cells.

Astrocytes

*note which ones are CNS/PNS

(largest and most numerous of glial cells)

- form a blood brain barrier
- interspersed between blood vessels and neurons in the brain
- form a final filter for all materials that reach the neurons from the bloodstream

CNS (my guess since it's in brain)

13

State the function and location of each of the six types of glial cells.

Microglia

*note which ones are CNS/PNS

phagocytic cells within the CNS

- mobile and injest foreign and degenerated material

14

State the function and location of each of the six types of glial cells.

Ependymal cells

*note which ones are CNS/PNS

cuboidally shaped cells that line ventricles (fluid- filled spaces) of the brain and central of spinal cord

- secrete the cerebral spinal fluid (CSF) of the CNS

15

State the function and location of each of the six types of glial cells.

Satellite cells

*note which ones are CNS/PNS

supporting cells found in ganglia

in PNS

16

Differentiate myelin and myelin sheath.

Myelin shealths: electrically insulating layers around axons

Myelin: insulating propery of myelin sheaths, derived from a lipid material in their cytoplasm

17

Explain the phenomenon of nervous impulse transmission including depolarization, repolarization, threshold, the role of the sodium-potassium pump, and the role of neurotransmitters.

Depolarization

Depolarization: when a neuron is stimulated, the positively charged extracellular sodium ions readily diffuse back through the cell membrane, a momentary change in electric potential occurs and this constitutes depolarization.

18

Explain the phenomenon of nervous impulse transmission including depolarization, repolarization, threshold, the role of the sodium-potassium pump, and the role of neurotransmitters.

Repolarization

Repolarization: when enough sodium ions diffuse into the cell to cause a charge "reversal" this makes the membrane temporarily permeable to potassium and enough potassium ions rush out of the cell to re-establish the original resting voltage (repolarization)

19

Explain the phenomenon of nervous impulse transmission including depolarization, repolarization, threshold, the role of the sodium-potassium pump, and the role of neurotransmitters.

Threshold

Threshold: when depolarization reaches a critical level called the threshold at any point on the cell membrane, it becomes temporarily permeable to sodium

- sodium rushes in by simple diffusion

20

Explain the phenomenon of nervous impulse transmission including depolarization, repolarization, threshold, the role of the sodium-potassium pump, and the role of neurotransmitters.

Sodium- Potassium Pump

pumps three sodium ions out of the cells and two potassium ions into the cell for each ATP used

- creates a charge called resting potential
- creates a negatively charged cytoplasm so neurons can conduct electrical impulses
- establishes the resting differences in sodium and potassium concentrations inside and outside the cell

21

Explain the phenomenon of nervous impulse transmission including depolarization, repolarization, threshold, the role of the sodium-potassium pump, and the role of neurotransmitters.

Neurotransmitters

when electrical impulses reach the synapse, it initiates the release of a chem substance called neurotransmitter

- this chemicals diffuses across the synaptic gap, interacts with the cell membrane of the next neuron, and either initiates an impulse (excitatory neurotransmitter) or inhibits an impulse in the next cell (inhibitory neurotransmitter)

22

State how saltatory conduction differs from regular nervous impulses.

Myelinated neurons conduct impulses faster because depolarization occurs only at the junctions of the ensheathing neurolemmocytes.

- it "skips" over the neurolemmocytes themselves

23

Name the three basic types of cells with which a neuron can synapse.

- other neurons
- muscle cells
- glandular epithelial cells

24

Discuss the development of the nervous system including: neural plate, neural groove, neural tube, neural crests.

1. area of the ectoderm overlying the notochord thickens to form NEURAL PLATE

2. a few days later the neural plate invaginates longitudinally to form NEURAL GROOVE

3. groove deepens and finally pinches off surface of ectoderm to become NEURAL TUBE (this neural tube with from Brain (anteriorly) and Spinal Cord (posteriorly)

4. groups of cells on each side of Neural tube separate from it to form NEURAL CRESTS

- develop into sensory neurons, autonomic neurons, neurolemmocytes, chromaffin cells, and melanocytes

25

Describe the development of the nervous system including the three vesicle stage, the five vesicle stage, and the derivatives of each vesicle.

Three Vesicle Stage:

- Prosencephalon (forebrain)
- Mesencephalon (midbrain)
- Rhombencephalon (hindbrain)

Five Vesicle Stage:

Prosencephalon:
- Diencephalon
- Telencephalon

Mesencephalon (remains the same)

Rhombencephalon:
- Metencephalon
- Myelencephalon

Derivatives of Each:

(P) ---> Diencephalon ---> Thalamus, Hypothalamus, Epithalamus

(P) ---> Telencephalon ---> Cerebrum

(M) ---> (M) ---> (M)

(R) ---> Metencephalon ---> Pons, Cerebellum

(R) ---> Myencephalon ---> Medulla Oblongata

26

State the general function of the cerebrum.

major center of sensory perception, thought, memory, and motor output

27

State the general functions of the epithalamus.

produces hormone melatonin

28

State the general functions of the thalamus.

relay center for most general sensory impulses originating below the head

29

State the general functions of the hypothalamus.

1. regulates heart rate and blood pressure
2. thermoregulation (shivering, etc.)
3. water/electrolyte balance (ADH secretion, thirst center)
4. Hunger and satiety feelings
5. sleep/wakefulness regulation
6. sexual responses
7. production of major emotional states
8. production of several hormones acted on pituitary gland and 2 hormones released from pituitary gland : ADH and oxytocin

30

State the general functions of the mesencephalon.

reflex center for vision and hearing and contains motor nuclei for 3rd and 4th cranial nerves (oculomotor and trochlear)