Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology and Neuroscience Semester 2 > Reflexes > Flashcards

Reflexes Flashcards

1
Q

What is a reflex?

A

An involuntary, stereotyped (same type of response is provoked with the same type of stimulus) response to a stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are reflex circuits?

A

Begin with receptors
End with effectors
Do not reach consciousness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What type of circuits are reflex circuits?

A

Simplest circuits in the nervous system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are tendon jerk reflexes?

A

Muscle contractions produced by muscle stretch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What can tendon jerk reflexes be evoked from?

A

Many muscles where tendon is accessible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does tapping a tendon do?

A

Stretches muscle to which it is attached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does tapping a tendon elicit?

A

A monosynaptic reflex that produces contraction of the stretched muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the basic elements of a reflex circuit?

A

Element Example of tendon jerk reflex

  1. adequate stimulus e.g. tendon tap (muscle stretch)
  2. Receptor e.g. muscle spindle
  3. Afferent (sensory) neurone) e.g. La primary afferent
  4. Central synapses e.g. monosynaptic
  5. Efferent (motor) neurone e.g. alpha- motorneurone
  6. Effector e.g. skeletal muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What accompanies the tendon jerk reflex?

A

La reciprocal inhibition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is simultaneously evoked with the tendon jerk reflex?

A

Inhibition of antagonist muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is la reciprocal inhibition mediated by?

A

An interneurone- la inhibitory neurone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What type of pathway is the tendon jerk and la reciprocal inhibition?

A

Disynaptic (2 synapses)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does la reciprocal inhibition operate?

A

In each direction between antagonistic muscles at a joint- hence reciprocal inhibition e.g. stretch of quadriceps muscle causes inhibition of hamstring muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are excitation of muscle spindles responsible for?

A

Stretch reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the tendon jerk reflex useful for?

A

Clinically, but is a response to an artificial stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the stretch reflex?

A

Normal function of the monosynaptic reflex circuit

17
Q

What does prolonged stretch produce?

A

Prolonged contraction

18
Q

What to stretch reflex act to maintain?

A

Constant muscle length

19
Q

What is an example of a closed loop in the vestibulo-occular system?

A

Moving your finger but trying to concentrate on moving finger

20
Q

What is an example of a open loop in the vestibulo-occular system?

A

Looking at finger while moving head

21
Q

What do both the open and closed loop do in the vestibulo-occular system?

A

Stabilise the visual image

22
Q

What is visual pursuit?

A

Movements of object relative to eyes

23
Q

What is a control reflex?

A

Closed loop

Control some physiological variable e.g. stretch reflex control muscle length

24
Q

What does a stimulus trigger in a control reflex?

A

Actions which feedback on stimulus e.g. stretch of muscle leads to a reflex response (muscle contraction) which returns the muscle to its original length

25
Q

What is a protective reflex?

A

Open loop

26
Q

What does a protective reflex not affect?

A

Stimulus e.g. flexion withdrawal reflex

27
Q

What is a protective reflex accompanied by?

A

Crossed extensor reflex (both are polysynaptic)

28
Q

What are flexor reflex and crossed extensor reflex mediated by?

A

Chains of interneurons- polysynaptic (many synapses)

29
Q

What do excitatory and inhibitory interneurones produce?

A

Appropriate actions on different motoneurone pools

30
Q

What is an example of pathways showing divergence?

A

Motoneurones with actions at hip

31
Q

what is the carotid sinus baroreceptor reflex?

A

Autonomic reflex regulating blood pressure

32
Q

What does the carotid sinus baroreceptor reflex control?

A

Heart rate and force of contraction (cardiac output)

Diameter of blood vessels (peripheral resistance)

33
Q

What are the two ways to change blood pressure

A

BP= CO x TPR

I.e. Cardiac output or total peripheral resistance

34
Q

What do reflexes involve?

A

Both somatic and autonomic nervous systems

35
Q

What is the somatic nervous system involved in with regards to reflexes?

A

(Skeletal muscles)

Spinal cord/ brain stem- mainly control movement of limbs and eyes

36
Q

What is the autonomic nervous system involved in with regards to reflexes?

A

(Smooth muscles)

Mainly control physiological system

37
Q

Why does the responses being automatic and rapid well suit reflex responses?

A

Well suited to processes of continuous regulation e.g. baroreceptor
Suited to rapid protextice responses e.g. flexion withdrawal reflex

38
Q

Why are reflex circuits used by higher centres?

A

Spinal reflex circuits are used descending systems to control movement

Physiology and Neuroscience Semester 2 (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions