COM 2 Physiology week 2

Question 1

Where is the motor cortex found in + anterior to what

Answer 1

Found in Posterior third of the frontal lobes, anterior to the central sulcus

Question 2

What does the motor cortex work with

Answer 2

Somatosensory cortex

Question 2

Where is the primary Motor cortex located

Answer 2

Located in the precentral gyrus

Question 3

In the primary motor cortex, what does the:
-Lateral
-Middle
-Medial
parts represent

Answer 3

• Lateral: Face/mouth
  -Middle: Arm/hand
  -Medial:Trunk/Leg

Question 4

What is the function of the primary motor cortex/what it controls

Answer 4

• Controls patterns of movement

Question 5

Where is the premotor area located

Answer 5

Anterior to the primary motor cortex

Question 6

What does the premotor area generate more of

Answer 6

Generates more complex motor patterns

Question 7

What does the premotor area work via

Answer 7

• Direct input to the primary motor cortex
  -Indirect input via the basal ganglia and thalamus

Question 8

What does the premotor area contain+ when is the contents active

Answer 8

• Contains mirror neurons
  -Active durgin performance or observation of tasks

Question 9

What are mirror neurons in the premotor area important for

Answer 9

Imitation and understanding others actions

Question 10

Where is the supplemetary motor area located

Answer 10

Within the longitudinal fissure

Question 11

What does the supplementary motor area activate+ what does it coordinate

Answer 11

Bilateral movements
It coordinates whole body movements, head/eye positions and posture

Question 12

What does the supplememtary motor area work alongside+ why

Answer 12

Works alongside the premotor and primary motor cortex,for FINE CONTROL

Question 13

Name the 4 specialised motor areas in the human cortex

Answer 13

-Brocas Area
-Voluntary eye movement field
-Head rotation area
-Area for hand skills

Question 14

What is Broca’s area also known as

Answer 14

Motor speech area

Question 15

Where is Broca’s area located + anterior to what

Answer 15

It is located just above the Sylvian fissure, anterior to primary motor cortex

Question 16

What is Brocas Area responsible for

Answer 16

Word formation

Question 17

What does damage in Broca’s area impair

Answer 17

It impairs the ability to speak coherent words

Question 18

Broca’s area works with another area to coordinate what?

Answer 18

To coordinate respiration an speech

Question 19

Where is the voluntary eye movement field located

Answer 19

Just above Broca’s area in the premotor cortex

Question 20

What does voluntary eye movement field control+ what does damage lead to

Answer 20

It controls voluntary eye movement and blinking
-Damage causes eyes to involuntary fix on objects

Question 21

Where is the head rotation area found higher in

Answer 21

Found higher in the motor association area

Question 22

What does the head rotation area control

Answer 22

Controls head rotation

Question 23

Where is the area for hand skills located - anterior to what

Answer 23

Anterior to the primary motor cortex

Question 24

What is Area for hand skills responsible for

Answer 24

Coordinated hand movements

Question 25

What does damage to the area for hand skills lead to

Answer 25

Leads to motor apraxia

Question 26

In Motor signal transmission, to the muscles : -They travel directly via what tract? -And indirectly through what+ e.g

Answer 26

- Directly via the corticospinal tract -Indirectly through accessory pathways involving: -Basal ganglia -Cerebellum -Brain stem nuclei

Question 27

What is the main output pathways from the motor cortex

Answer 27

Corticospinal tract

Question 28

Explain where the corticospinal tract orginiates from

Answer 28

30% from primary motor cortex 30% from premotor and supplementary motor areas 40% from somatosensory areas

Question 29

In the corticospinal tract what do the signals pass through and form -Where do the fibers cross+ enter

Answer 29

- Internal capsule to the brainstem and forms the medullary pyramids -Fibers cross in the lower medulla and enter the lateral corticospinal tract

Question 30

In the corticospinal tract where does the fibers terminate

Answer 30

- Mostly on interneurons in spinal cord gray matter -Some on sensory relay neurons -Few directly on motor neurons

Question 31

What is the corticospinal tract split into

Answer 31

Lateral and ventral

Question 32

In the ventral corticospinal tract , where do the fibers descend and where + explain their corssing

Answer 32

- Some fibers dont cross in the medulla -Descend ipsilaterally in the ventral corticospinal tract -Cross later

Question 33

What are Betz cells + what do the fibers carry

Answer 33

- Large pyrimidal cells in the primary motor cortex -Carry tonic signals

Question 34

Explain the characteristics of the axons in Betz cells

Answer 34

They are fast conducting

Question 35

Name the 6 other pathways from the moto cortex

Answer 35

1. Betz cell collaterals 2.Basal ganglia pathway 3.Rubrospinal pathway 4.Reticulospinal and vestibulospinal pathways 5.Pontocerebellar pathways 6.Olivocerebellar pathway

Question 36

Where does Betz cell collaterals send short branches back to + what do they inhibit and why

Answer 36

Back to the cortex -Inhibit neighbouring areas to sharpen signal focus

Question 37

In the basal ganglia pathway were does the fibers go to + What does this pathway infuence

Answer 37

Caudate nucleus and putamen -Influences postural muscle control

Question 38

In the rubrospinal pathway were do most fibers go to

Answer 38

Red nuclei of the midbrain

Question 39

In the reticulospinal and vestibulospinal pathways where do the fibers go + what does it control and via what tracts

Answer 39

- Fibers go to reticular formation and vestibular nuclei -Controls motor function via reticulospinal/vestibulospinal tracts

Question 40

In the pontocerebellar pathway, -Where do the fibers synapse -Where are the signals sent to and via what

Answer 40

- Synapse in pontine nuclei -Signals sent to cerebellar hemispheres via pontocerebellar fibers

Question 41

In the olivocerebellar pathway, -Where do collaterals terminate -Where do they send olivocerebellar fibers to

Answer 41

- Collaterals terminate in the inferior olivary nucleus -Send the olivocerebellar fibers to the cerebellum

Question 42

Name the 5 incoming sensory fiber pathways that go to the motor cortex - say where its from

Answer 42

1.From nearby cortical areas 2. From oppsoite hemisphere 3. From the ventrobasal thalamus 4.From the ventrolateral and ventroanterior thalamic nuclei 5.From intralaminar thalalmic nuclei

Question 43

In Incoming signals From the nearby cortical areas where do the signals come from

Answer 43

-somatosensory areas -Frontal cortex -visual and auditroy cortices

Question 44

In incoming signals from the Opposite hemisphere , where do the signals pass through

Answer 44

Corpus callosum

Question 45

In incoming signals from the ventrobasal Thalamus, what type of signals does it carry

Answer 45

Carries tactile,joint and muscle sensory signals

Question 46

In the incoming signals from the ventrolateral and ventroanterior thalamic nuclei : -Where does it recieve input from -What do they help to coordinate

Answer 46

- Recieve input from the cerebellum and basal ganglia -They help to coordinate moto control

Question 47

In the incoming signals from the intralaminar thalamic nuclei , What does does it regulate

Answer 47

Regulates the general excitability of the motor cortex

Question 48

Where is the red nucleus located

Answer 48

- In the midbrain

Question 49

What does the red nucleus signals recieve signals from

Answer 49

- Primary motor cortex -Corticospinal tract

Question 50

What does the mangicellular part of the red nucleus give rise to

Answer 50

The rubrospinal tract

Question 51

Where does the rubrospinal tract cross over and it runs parallel to where?

Answer 51

- Crosses over in the brainstem and runs parallel to the corticospinal tract in the spinal cord

Question 52

What is the function of the rubrospinal tract

Answer 52

-Alterntative motor pathway for voluntary movement control

Question 53

Where does the corticospinal and rubrospinal fibers mainly terminate + in areas of fine motor control where do they synapse?

Answer 53

On the interneurons in the spinal cord -Directly on anterior motor neurons

Question 54

What does stretch reflex help woth

Answer 54

It helps smooth out brain-initated movements

Question 55

What does recipriocal inhibition ensure

Answer 55

That when one muscle contracts, its antagonist relaxes

Question 56

What is a stroke caused by

Answer 56

-Hemorrhage -Thrombosis

Question 57

What does a stroke affect

Answer 57

Motor cortex or corticospinal tract

Question 58

What does the removal of primary motor cortex result in

Answer 58

- Loss of voluntary fine movements -Gross movements

Question 59

What is muscle spasticity caused by

Answer 59

- Damage to the motor cortex and adjacent areas like basal gangloa

Question 60

What does muscle spasticity lead to

Answer 60

- Hypotonia -Disinhibition of brainstem motor nuclei

Question 61

What is the brainstem composed of

Answer 61

-Medulla -Pons Midbrain

Question 62

What does the brain stem serve as

Answer 62

Central comman center

Question 63

Name 4 motor control functions of the brainstem

Answer 63

-Control of Respiration -Control of cardiovascular systme -Control of eye movements -Control of equilibirum

Question 64

What is the reticular nuclei divided into

Answer 64

- Pontine reticular nuclei -Medullary reticular nuclei

Question 65

Explain where the Pontine reticular nuclei is : -Located -Explain its excitability -Where does it recieve input from

Answer 65

- Located posterior-laterally in the pons -High excitability to antigravity muscles -Recieves input from vestibular nuclei and deep cerebellar nuclei

Question 66

Explain where the medullary reticular nuclei is: -Located -its inhibitory -What it recieves input from

Answer 66

- Located ventromedially in the medulla -Inhibitory to antigravity muscles -Recieves input from: -Corticospinal tract -Rubrospinal tract

Question 67

What does the vestibular nuclei work with and to stimulate what ? + what does it provide

Answer 67

Vestibular nuclei works with pontine reticular nuclei to stimulate antigravity -Provides strong support to the pontine reticular system

Question 68

Name the 2 tracts the vestibular nuclei transmits ecxcitatory signlas via

Answer 68

-Lateral vestibulospinal tract -Medial vestibulospinal tract

Question 69

Where is the vestibular apparatus located

Answer 69

- In the bony labyrinth

Question 70

Name the 4 components of the membranos labyrinth

Answer 70

- Cochlea -3 semicircular canals -Utricle -Saccule

Question 71

What does the semicircular canals in the ear detect

Answer 71

- Detect rotational movement

Question 72

what does the utricle and saccle detect

Answer 72

-Utricle – detects head position in the horizontal plane Saccule – detects head position in the vertical plane

Question 73

Where is the Macula found inside

Answer 73

- Inside the utricle and saccule

Question 74

What does the macua contain

Answer 74

- Hair cells, cilia and statoconia

Question 75

What does each hair cell have

Answer 75

Stereocilla and 1 large kinocilium

Question 76

Stereocilia decreases in lenght away from what?

Answer 76

Kinocilium

Question 77

What links each stereocilium to kinocikium

Answer 77

Tiny fimalentous attachments

Question 78

Explain the mechanism of signal generation -In Bending towards the kinocilium -In bending away from the kinocilium

Answer 78

Bending toward the kinocilium: pulls the attachments, opens ion channels, positive ions enter → depolarization. Bending away from the kinocilium: relaxes the attachments, closes channels → hyperpolarization.

Question 79

What does bending toward the kinocilium icause

Answer 79

Increased firing

Question 80

What does bending away from the kinocilium cause

Answer 80

Decreases firing

Question 81

Name the components in the semicircular ducts+ position

Answer 81

- Anterior ducts-Vertical,forward -Posterior ducts-Vertical, backward -Lateral ducts- Horizontal

Question 82

What does each semi circular duct end in

Answer 82

Ampulla filled with endoly,h

Question 83

What is inside the ampula

Answer 83

Crista ampullaris

Question 84

Explain the mechanism of detection of head rotation by the semicircular Ducts : starting with: -Angular acceretion

Answer 84

Angular acceleration (head rotation) causes endolymph to lag due to inertia. This results in relative fluid movement opposite to the direction of rotation. The fluid movement bends the cupula, which stimulates hair cells in the crista ampullaris

Question 85

Explain the discharge pattern from hair cells in: -Resting state- what rate do the cells fire at -Start of rotation- What causes -sustained rotation

Answer 85

Resting state: Hair cells fire at a tonic rate Start of rotation: Bending of hairs increases discharge rate. Sustained rotation: Discharge rate gradually returns to baseline due to adaptation

Question 86

Explain what happens in the adaption mechanism starting w endolymph, what it cathes up with -Where does the cupula return to

Answer 86

- Endolymph eventually catches up with duct motion due to resistance. Cupula then returns to center due to elastic recoil

Question 87

What is the babinksi reflex

Answer 87

- A neurological test to asses the corticospinal tract function

Question 88

How is the babinski test reflex conducted

Answer 88

- A tool is stroked from the heel along the outer edge to the base of the big toe

Question 89

Explain a negative and positive result in Babinksi reflex

Answer 89

- Negative-Toel curls down -Abnormal-Big toe bends upward

Question 90

What is the defintion of menires Disease+ what it causes

Answer 90

A chronic inner ear disorder causing : -Vetigo -Tinnitus -Hearing loss

Question 91

What causes of Menieres disease-

Answer 91

- Fuild buildup in the labyrinth

Question 92

What are the treatments for Menieres disease

Answer 92

- No cure