A&P 2.3 nerves Flashcards Preview

A&P 2 > A&P 2.3 nerves > Flashcards

Flashcards in A&P 2.3 nerves Deck (28)
0

Neuron

3 parts

Dendrite
Axon
Cell body

1

Nerves

Definition

Bundles of axons in the PNS
All spinal nerves and many cranial nerves are mixed; they have both sensory and motor

2

Mixed nerve

Sensory and motor component

3

Tracts

Bundles of nerves in the central nervous system
Most tracts contain fibers going in one direction

4

Myelin

Sheaths - multilayer wrappings around most axons of most neurons
Formed by glial cells
Each cell wraps a very small portion of the axon
Each axon is separated by unmyelionated nodes which are going to speed impulse conduction

5

Nodes of ranvier

Unmyelionated portion of the axion

6

Myelin producing cells

2

Schwann cells

Oligodengrocytes

7

Schwann cells

Glial cells in the PNS that form myelin sheaths
A single Schwann cell wraps around a 1mm segment of a single axon length

8

Oligodendrocytes

"Cells with branches"
Glial cells in the CNS that form myelin sheaths
Each oligodendrocyte extends (15-50 branches)
Multiple branches each of which creates a myelin sheath on multiple axons

9

White and grey matter

Located

Located in brain and spinal cord

10

White matter

Is regions of the CNS containing myelinated axons

ONLY IN CNS

Superhighway, has super fast speed

11

Grey matter

Found in the CNS

Contains little or no myelin
Comprised of mostly cell bodies, dendrites, ends of axons and unmyelionated axons

ONLY IN CNS

Where thought process happens

12

Multiple sclerosis

Autoimmune disease that causes progressive destruction of the myelin sheaths in the CNS
Slowing down nerve impulse conduction

Multiple regions of the nervous system
Sclerosis- plaque formation

13

Ventral/dorsal roots

Important. P. 431

Every spinal nerve connects to the spinal cord by two roots:

Ventral
Dorsal

14

Dorsal roots

Contain ONLY sensory neurons entering the cord

15

Ventral roots

Contain ONLY motor neurons

16

Reflex arc

Defined

A signal conduction route to and from the CNS
The most common form of reflex arc is the three-neuron arc
Fast and involuntary actions in response to a stimulus
****Reflex arc IS THE SIMPLEST FORM OF INTEGRATION (processing of stimulus)
Shortest pathway from a stimulus to a response
Consists of seven components

17

7 components of the reflex arc

Stimulus
Sensory receptor
Sensory neuron
Integrating center
Motor neuron
Effector
Response

18

Stimulus

Change in (internal/external) environment to stimulate a sensory receptor

19

Sensory receptor

Dendrite or specialized structure that stimulates a dendrite.
If the stimulus is strong enough it will create an impulse (action potential) to be generated in a sensory neuron

20

Sensory neuron

Conducts an impulse from receptors to CNS
Dorsal root if it is a SPINAL REFLEX NOT CRANIAL REFLEX
Moves to integrating center

21

Integrating center

Sensory neurons synapse (space between 2 neurons where communication happens) with motor neurons or with an inter neuron that synapses with motor neuron

22

Motor neuron

Conducts a nerve impulse from the CNS to an effector

23

Effector

A muscle or a gland

24

Response

A muscle contraction or relaxation

OR

Glandular response to secrete or inhibit secretion

25

Superaspinatus

A, I, O

A- abduct the shoulder; stabilize the head of the humerus in glenoid cavity

O- superaspinatus fossa of the scapula

I - greater tubercle of the humerus

26

Infraspinatus

A, I, O

A- laterally rotate the shoulder, adduct the shoulder, extension of the humerus

O - infraspinous fossa of the scapula

I - greater tubercle of the humerus

27

Rotator cuff

4 muscles

Superaspinatus
Infraspinatus
Teres minor
Subscapularis

Superaspinatus runs deep to the trapezius

S,I,T,S