12.1 Nervous Tissue

Question 1

BRAIN:

Answer 1

• CNS
• SURR. BY SKULL
• 100 BIL. NEURONS

Question 2

SPINAL CORD:

Answer 2

• CNS
• SURR. BY BONE OF VERTEBRAL COLUMN
• 100 MIL. NEURONS

Question 3

CRANIAL NERVES:

Answer 3

• PNS
• 12 PAIRS (CN I-XII)
• EMERGE FROM BASE OF THE BRAIN

Question 4

SPINAL NERVES:

Answer 4

• PNS
• 31 PAIRS
• EMERGE FROM SPINAL CORD
• EACH SERVES SPECIFIC REGION

Question 5

SENSORY RECEPTORS:

Answer 5

• PNS

- SPECIALIZED CELLS THAT MONITOR CHANGES IN (INTERNAL/EXTERNAL) ENVIRONMENT

Question 6

GANGLIA:

Answer 6

• PNS
• MASSES OF NERVOUS TISSUE
• CONSIST OF NEURON CELL BODIES OUTSIDE BRAIN AND SPINAL CORD

Question 7

ENTERIC PLEXUS:

Answer 7

• PNS
• NERVE NETWORK IN G.I. TRACT
• HELP REGULATING DIGESTIVE SYSTEM

Question 8

NERVOUS SYSTEM: TAKS:

Answer 8

• SMELL
• TOUCH
• TEMPERATURE
• PRODUCING SPEECH
• REMEMBERING/MEMORY
• SIGNALS TO CONTROL BODY MOVEMENT
• REGULATE OPERATIONS OF INTERNAL ORGANS

Question 9

NERVOUS SYSTEM: BASIC FUNCTIONS:

Answer 9

• INPUT FROM SENSORY RECEPTORS AND SENSORY NERVES TO CNS
• INTEGRATION (PERCEPTION, ANALYZING, AND STORING INFORMATION)
• MOTOR ACTIVITY VIA EFFERENT NERVES (OR EFFECTORS) SIGNALS TO MUSCLES AND GLANDS

Question 10

NERVOUS SYSTEM: HISTOLOGY: (1)

Answer 10

• NERVOUS TISSUES WITH NEURONS:
  = PROVIDES MOST OF THE UNIQUE FUNCTIONS
• NEUROGLIA:
  = SUPPORT, NOURISH, AND PROTECT NEURONS
• NEURONS:
  = POSSES ELECTRICAL EXCITABILITY

Question 11

NERVOUS SYSTEM: HISTOLOGY: (2)

Answer 11

• STIMULUS:
  = ANY CHAGE IN THE ENVIRONMENT (THAT IS STRONG ENOUGH TO INITIATE AS ACTION POTENTIAL)
• ACTION POTENTIAL: ( = NERVE IMPULSE)
  = ELECTRICAL SIGNAL THAT PROPAGATES ALONG THE SURFACE OF MEMBRANE OF A NEURON

Question 12

ANATOMY: NEURON:

Answer 12

a) CELL BODY: NUCLEUS, CYTOPLASM, ORGANELLES
b) DENDRITES: HIGHLY BRANCHED
= CARRY IMPULSES FROM SENSORY TO CELL BODY
= RECEIVING PART”
c) AXON: CONDUCT AWAY FROM CELL BODY TO:
= ANOTHER NEURON
= MUSCLE
= GLAND
d) AXON TERMINALS: CONTAIN SYNAPTIC VESICLES THAT RELEASE NEUROTRANSMITTERS

Question 13

CLASS OF NEURON: BY STRUCTURE: a) MULTIPOLAR:

Answer 13

• HAVE SEVERAL DENDRITES AND ONE AXON

- MOST COMMON TYPE; THE REGULAR TYPE

Question 14

CLASS OF NEURON: BY STRUCTURE: b) BIPOLAR:

Answer 14

• HAVE ONE DENDRITE AND ONE AXON

- ex) THOSE IN RETINA OF EYE AND INNER EAR

Question 15

CLASS OF NEURON: BY STRUCTURE: c) UNIPOLAR:

Answer 15

• HAVE FUSED DENDRITE AND AXON

- ex) SENSORY NEURONS OF SPINAL NERVES

Question 16

CLASS OF NEURON: BY FUNCTION: a) SENSORY:

Answer 16

• “AFFERENT”

- CONVEY IMPULSES INTO CNS

Question 17

CLASS OF NEURON: BY FUNCTION: b) MOTOR:

Answer 17

• “EFFERENT”

- CONVEY IMPULSES FROM CNS THROUGH PNS TO EFFECTORS (MUSCLES/GLANDS)

Question 18

CLASS OF NEURON: BY FUNCTION: c) INTERNEURONS:

Answer 18

• “ASSOCIATION NEURONS”
• TRANSMIT IMPULSES BETWEEN NEURONS
• MOST ARE WITHIN CNS

Question 19

NEUROGLIAS: GENERAL:

Answer 19

• SUPPORT, NOURISH, AND PROTECT NEURONS
• ** CRITICAL FOR HOMEOSTASIS OF INTERSTITIAL FLUID AROUND NEURONS
• SMALLER BUT MUCH NUMEROUS THAN NEURONS
  = MAKE UP ABOUT HALF THE VOLUME OF CNS

Question 20

NEUROGLIAS: FUNCTION:

Answer 20

• DO NOT CONDUCT NERVE IMPULSES

- IN CASE OF INJURY/DISEASE, CAN MULTIPLY TO FILL IN SPACE FORMERLY OCCUPIED BY NEURONS

Question 21

NEUROGLIAS: TYPES: a) ASTROCYTES:

Answer 21

• IN CNS

- FORM BLOOD-BRAIN BARRIER

Question 22

NEUROGLIAS: TYPES: b) OLIGODENDROCYTES:

Answer 22

• IN CNS

- PRODUCE MYELIN IN CNS NEURONS

Question 23

NEUROGLIAS: TYPES: c) MICROGLIA:

Answer 23

• IN CNS

- PROTECTS CNS CELLS FROM DISEASE

Question 24

NEUROGLIAS: TYPES: d) EPENDYMAL CELLS:

Answer 24

• IN CNS
• LINE THE VENTRICLES OF BRAIN AND SPINAL CORD CANAL
• FORM THE CSF IN VENTRICLES

Question 25

NEUROGLIAS: TYPES: e) SCHWANN CELLS:

Answer 25

- IN PNS | - PRODUCE MYELIN IN PNS NEURONS

Question 26

NEUROGLIAS: TYPES: f) SATELLITE CELLS:

Answer 26

- IN PNS | - SUPPORT NEURONS IN PNS GANGLIA

Question 27

MYELINATION: MYELIN:

Answer 27

- FUNCTIONS: a) INSULATES THE AXON b) SPEEDS UP THE NERVE IMPULSE - "NODES OF RANVIER" = GAPS IN MYELINS - DISEASES THAT DESTROY MYLIN: a) MULTIPLE SCLEROSIS (IMMUNE SYSTEM EATS MYELIN) b) TAY-SACH

Question 28

COLLECTION OF NERVOUS TISSUE: CLUSTER OF NEURON CELL BODIES:

Answer 28

- IN CNS: "NUCLEUS" | - IN PNS: "GANGLION"

Question 29

COLLECTION OF NERVOUS TISSUE: BUNDLE OF AXONS:

Answer 29

- IN CNS: "TRACT" | - IN PNS: "NERVE"

Question 30

COLLECTION OF NERVOUS TISSUE: WHITE MATTER:

Answer 30

- CONTAINS PRIMARILY MYELINATED AXONS

Question 31

COLLECTION OF NERVOUS TISSUE: GRAY MATTER:

Answer 31

- CONTAINS: a) CELL BODIES b) DENDRITES c) UNMYELINATED AXONS d) AXON TERMINALS e) NEUROGLIA

Question 32

LOCATION OF GRAY AND WHITE MATTER: IN BRAIN:

Answer 32

GRAY MATTER (THIN CORTEX) SURROUNDS WHITE MATTER (TRACT)

Question 33

LOCATION OF GRAY AND WHITE MATTER: IN SPINAL CORD:

Answer 33

WHITE MATTER (TRACT) SURROUNDS GRAY MATTER ("H"/BUTTERFLY)

Question 34

NEURON REGENERATION: PNS:

Answer 34

AXONS AND DENDRITES IN PNS CAN BE REPAIRED IF: - CELL BODY IS INTACT - SCHWANN CELL IS FUNCTIONAL

Question 35

NEURON REGENERATION: CNS:

Answer 35

- VERY LIMITED | - INHIBITED BY NEUROGLIA AND BY LACK OF FETAL GROWTH-STIMULATOR CUES

Question 36

ACTION POTENTIAL ( = NERVE IMPULSE):

Answer 36

- ALLOWS FOR COMMUNICATION BETWEEN NEURON | - PART OF A SERIES OF EVENTS THAT ACTIVATE CELL MEMBRANE IN NEURON OR MUSCLE FIBER

Question 37

ACTION POTENTIAL REQUIRES:

Answer 37

a) RESTING MEMBRANE POTENTIAL (A CHARGE DIFFERENCE ACROSS CELL MEMBRANE) (POLARIZATION) b) ION CHANNELS: ALLOW IONS TO MOVE BY DIFFUSION FROM HIGH TO LOW CONCENTRATION, MAKING RESTING MEMBRANE POTENTIAL = LEAKAGE CHANNELS ALLOW ION S TO LEAK THROUGH = GATE CHANNELS OPEN AND CLOSE ON COMMAND

Question 38

ACTION POTENTIAL SEQUENCE (1): INITIAL:

Answer 38

1) INITIAL EVENT ( = STIMULUS) IS REQUIRED - > TRIGGERS RESTING MEMBRANE TO BECOME MORE PERMEABLE TO Na+ - > CAUSES ENOUGH Na+ TO ENTER CELL TO REACH THRESHOLD (~-55mv) - > WHEN REACHED THE THRESHOLD, ACTION POTENTIAL RISES

Question 39

ACTION POTENTIAL SEQUENCE (2): DEPOLARIZATING:

Answer 39

2) DEPOLARIZING PHASE: - > Na+ CHANNEL OPENS - > AS Na+ ENTER CELL, MEMBRANE POTENTIAL RISES AND BECOMES POSITIVE (-70mv -> 0mv -> +30mv)

Question 40

ACTION POTENTIAL SEQUENCE (3): REPOLARIZING:

Answer 40

3) REPOLARIZING PHASE: - > K+ CHANNEL OPENS - > AS K+ LEAVE CELL, MEMBRANE POTENTIAL RETURNS TO RESTING VALUE

Question 41

CONDUCTION OF NERVE IMPULSE: PROPAGATION (전달/전파):

Answer 41

- WHEN NERVE IMPULSE TRAVELS (FROM AXON HILLOCK ALONG THE AXON TO AXON TERMINAL - EACH SECTION TRIGGERS THE ADJACENT SEGMENT DISTALLY

Question 42

TYPES OF CONDUCTION:

Answer 42

a) CONTINUOUS CONDUCTION: - > IN UNMYELINATED AXONS - > CURRENTS FLOW ACROSS ADJACENT PORTIONS OF PLASMA MEMBRANE b) SALTATORY CONDUCTION: - > IN MYELINATED AXONS - > NODES OF RANVIER ALLOWS THE "LEAP" OF IMPULSES - > FASTER FORM

Question 43

FACTORS THAT INCREASE RATE OF CONDUCTION:

Answer 43

a) MYELIN b) LARGE DIAMETER c) WARM NERVE FIBER

Question 44

SYNAPTIC TRANSMISSION:

Answer 44

- ONE-WAY TRANSMISSION - ALLOWS NEURONS TO COMMUNICATE WITH OTHER NEURONS OR EFFECTORS (NEUROMUSCULAR AND NEUROGLANDULAR JUNCTION) - TRIGGERED BY ACTION POTENTIAL

Question 45

COMPONENTS OF SYNAPSE:

Answer 45

``` a) PRE-SYNAPTIC NEURON: "SENDING NEURON" = RELEASES NEUROTRANSMITTER b) SYNAPTIC CLEFT: = SPACE BETWEEN NEURONS c) POST-SYNAPTIC NEURON: "RECEIVING NEURON" ```

Question 46

SYNAPTIC TRANSMISSION PROCESS:

Answer 46

1) AP ARRIVES AT PRESYN. NEURON'S END BULB AND OPENS Ca+ CHANNEL 2) Ca+ FLOW INTO PRESYN. CYTOSOL 3) INCREASED Ca+ CONCENTRATION CAUSE EXOCYTOSIS OF SYNAPTIC VESICLES, RELEASING NT MOLECULES INTO THE CLEFT 4) NT DIFFUSE ACROSS CLEFT AND BINDS TO RECEPTOR IN POSTSYN. CELL MEMBRANE = NT ACTS AS CHEMICAL TRIGGER = OPENS ION CHANNELS 5) POSTSYN. CELL MEMBRANE MAY BE DEPOLARIZED OR HYPERPOLARIZED 6) IF THRESHOLD IS REACHED, POSTSYN. ACTION POTENTIAL RESULTS -> NERVE IMPULSE TRIGGERED 7) NT REMOVED FROM CLEFT VIA: a) DIFFUSION b) DISTRUCTION BY ENZYME c) TRANSPORT BACK TO PRESYN. CELL (RECYCLING)