March 18, 2015 --> Nerves (121-136) Flashcards Preview

BOARD: Biochemistry (Dental Decks) > March 18, 2015 --> Nerves (121-136) > Flashcards

Flashcards in March 18, 2015 --> Nerves (121-136) Deck (45):
1

When a patient experiences unwanted moments, such as involuntary jerking movements of an arm or leg, which disorders might be implicated? Which part of the nervous system might be affected?

-Parkinson's disease and Huntington's disease
-Basal Ganglia is affected

2

The combination of what two things are often referred to as the lentiform nucleus

Putamen and globus pallidus

3

Which two parts of the nervous system are considered large collections of nuclei that modify movement on a minute-to-minute basis?

Basal Ganglia
Cerebellum

4

The cerebral cortex sends information to both the basal ganglia and cerebellum and they both send information back to the cortex via what structure? what two pathways are used to do this?

Via the thalamus
- Direct and Indirect pathway

5

The direct and indirect pathways for communication both use what neurotransmitter?

Dopamine

6

What affect does the neurotransmitter have on direct and indirect pathways respectively?

Direct: Dopamine is excitatory with an overall net excitatory role

Indirect: Dopamine is inhibitory

7

The output of the cerebellum is (inhibitory,excitatory) while the basal ganglia are (inhibitory, excitatory)

Cerebellum: excitatory
Basal ganglia: inhibitory

8

Basic function of cerebellum?

Function is to maintain equilibrium and muscle coordination

9

What are the major parts of the extrapyramidal system?

The subcortical nuclei
- This includes the caudate nucleus, putamen and globes pallidus

10

What is the classic neurotransmitter of autonomic ganglia

Acetylcholine

11

What are the two classes of acetylcholine receptors in autonomic ganglia

Nicotinic receptors
Muscarinic receptors

12

Nicotinic receptors are stimulated by what?

Ach and Nicotine
NOT by muscarine

13

Where are nicotinic receptors found and what do they produce?

-Found at ALL ganglionic synapses
-Also found at neuromuscular junctions and the adrenal medulla
**Produce excitation

14

Muscarinic receptors are stimulated by what?

ACh and muscarine
NOT by nicotine

15

Where are muscarinic receptors found?

Found at target organs when ACh is released by postganglionic neurons including heart, smooth muscle and glands

16

The fast EPSP (excitatory postsynaptic potentials) results from activation of what receptors?

Activation of nicotinic receptors, which cause ion channels to open

17

Muscarinic receptors are blocked by what?

Atropine

18

Nicotinic receptors are blocked by what?

hexamethonium and curare

19

The slow EPSP is mediated by which receptors?

Muscarinic receptors that inhibit the M current, a current produced by conductance of potassium

20

Fibers that secrete acetylcholine are said to be what? Fibers that secrete norepinephrine are said to be what?

ACh: Cholinergic
Norepinephrine: Adrenergic

21

What are the cholinergic effects of PREGANGLIONIC autonomic neurons?

Excitatory

22

What are the cholinergic effects of POSTGANGLIONIC parasympathetic fibers?

Excitatory or inhibitory

23

Which neurons are cholinergic?

- All preganglionic nerons in both sympathetic and parasympathetic nervous systems
- Either all or almost all of the postganglionic neurons of the parasympathetic system

24

Which neurons are adrenergic?

Most of the postganglionic sympathetic neurons
- except for the postganglionic sympathetic nerve fibers to the sweat glands, to the piloerector muscles of the hairs and to a very few blood vessels which are cholinergic

25

What are the two main types of adrenergic receptors in the ANS?

Alpha
Beta

26

Describe the locations of Alpha 1 and 2 receptors and the different effects they have on their targets

1: located on smooth muscle; produce excitation
2: located in presynaptic nerve terminals, platelets, fat cells, and walls of GI tract; Produce inhibition

27

Describe the locations of Beta 1 and 2 receptors and the different effects they have on their targets

1: Located in the heart; produces excitation (increased heart rate and contractility)
2: Located on smooth muscle; produces relaxation (dilation)

28

Which neurotransmitters stimulate alpha receptors? Which stimulate both alpha & beta receptors?

Alpha: Norepinephrine
Alpha & Beta: Epinephrine

29

What are the two main types of cholinergic receptors?

Nicotinic and muscarinic

30

T or F, ACh is released at the terminal sympathetic fibers of the heart

False, NOT released. Cardiac muscle is inhibited by acetylcholine

31

What enzyme breaks down Acetylcholine

Acetylcholinesterase (AChE)
- Rapidly breaks down ACh into acetate and choline after its release from the presynaptic terminal onto the muscle end-plate. If it is inhibited, there is prolongation of the end-plate potential

32

The pyramidal tract is also called what?

The corticospinal tract

33

The corticospinal tract carries messages for what?

Voluntary motor movement

34

The autonomic nervous system is a motor system that controls what things?

Smooth muscle
Cardiac muscle
Glands

- NOT skeletal muscle

35

2 classes of receptors based on the location of the stimuli in which the receptors respond:

1. Interoreceptors (viscerorecptors) - located in the body's internal environment
2. Exteroreceptors - receptors that respond to stimuli from body surface

36

Proprioreceptors are classified into which of the two receptor classes?

Interoreceptors

37

What are nocioceptors?

(and free nerve endings) are sensitive to pain

38

What is Adaptation in relation to nerves?

A property of certain receptors where the receptor becomes LESS RESPONSIVE or stops responding to repeated or continued stimuli of constant intensity. A decrease in the frequency of action potentials in an afferent neuron despite constant stimulus intensity

39

Which of the encapsulated nerve endings are considered touch and pressure receptors and which are stretch receptors?

Touch & Pressure
- Meissner's corpuscle
- Krause's corpuscle
- Ruffini's corpuscle
- Pacinian corpuscle

Stretch
- Muscle spindles
- Golgi tendon receptors

40

Describe the location of each of the 4 touch and pressure receptors that are encapsulated

Meissner's: Exteroceptors; epidermis, hairless skin
Krause's : Mucous membrane
Ruffini's : Dermis of skin, exteroceptors
Pacinian : Dermis of skin, joint capsules

41

Describe the function of each of the 4 touch and pressure receptors that are encapsulated

Meissner's : Discriminative touch: low frequency vibration
Krause's: Touch; low-frequency vibration; cold
Ruffini's : Crude and persistent touch; heat
Pacinian : Deep pressure; high frequency vibration; stretch

42

The PNS is subdivided into what 3 things?

1. Somatic Nervous System
2. Autonomic Nervous system
3. Enteric nervous system

43

Describe the somatic nervous system

Includes all nerves controlling the muscular system and external sensory receptors. External sense organs are receptors. Muscle fibers and gland cells are effectors

44

Describe autonomic nervous system

The organs of our body such as the heart, stomach and intestines. Largely works unconsciously. Has two divisions: Sympathetic nervous system and Parasympathetic nervous system

45

Difference between Pyramidal tracts and extra-pyramidal tracts?

-Corticospinal tracts are considered the "pyramidal" tracts. Usually involved with voluntary motor stimuli
- Other tracts (tectospinal, vestibulospinal, etc.) come from a variety of locations in brain and are considered the "extra-pyramidal" tracts. Generally associated with balance and muscle tone