Mod4-Obj1: The cerebrum

Question 1

The cerebrum

Answer 1

Largest part of the brain

• Divided along the midline into two hemispheres by the longitudinal fissure
• Separated from the cerebellum by the transverse fissure

Question 2

Cerebrum

Answer 2

Characterised by ridges (gyrus, gryi) and grooves (sulcus, sulci), increases the surface area, thus its functional capacity
-Each hemisphere is divided by sulci into five lobes: Frontal, parietal, temporal, occipital and insula

Question 3

Cerebral hemispheres

Answer 3

Each hemisphere is divided into structurally and functionally distinct regions

Question 4

Cerebral hemisphere: Gray matter

Answer 4

An outer layer of gray matter (2-4mm thick) cortex (neuron cell bodies)

Question 5

Cerebral hemispheres: white matter

Answer 5

A deeper region of white matter (fibres/axons)

Question 6

Cerebral hemispheres: basal nuclei

Answer 6

Clusters of grey matter deep within the white matter

Question 7

Cerebral cortex

Answer 7

Location of the conscious mind

• Conscious thought processes, intellectual functions, memory storage and processing
• Localises and interprets sensory input
• Regulation of skeletal muscle activity (voluntary motor area)

Question 8

The cortex of each cerebral hemisphere has 3 functional areas

Answer 8

1. ) Motor areas
2. ) Sensory areas
3. ) Association areas

Question 9

The cortex of each hemisphere…

Answer 9

• Deals with the sensory and motor functions of the opposite (contralateral) side of the body
• Has distinct functions (lateralisation)

Question 10

Hemispheric lateralisation

Answer 10

• 90% of people are represented by the diagram = left cerebral dominance
• 10% of people have the reverse = right cerebral dominance

Question 11

Left-brain functions

Answer 11

• Analytic thought
• Logic
• Language
• Science and maths

Question 12

Right-brain functions

Answer 12

• Holistic thought
• Intuition
• Creativity
• Art and music

Question 13

The primary motor cortex

Answer 13

Pre-central gyrus of the frontal lobe

-Plans and initiates all voluntary motor activity

Question 14

The primary motor cortex contains…

Answer 14

The cell bodies of upper motor neurons of somatic motor pathways

Question 15

The primary motor cortex directs…

Answer 15

Movement of skeletal muscles via somatic motor pathways, which control the contralateral side of the body

Question 16

Specific areas of the primary motor cortex are devoted to…

Answer 16

Controlling specific parts of the body

Question 17

The amount of motor cortex devoted to controlling a body part is…

Answer 17

Indicative of the complexity and precision of the movements of the body

e. g.) hands and face
- More neurons involved the greater distributed of neurons in the motor cortex

Question 18

The primary motor cortex: Premotor area (motor association area)

Answer 18

Co-ordinates muscles involved in learned motor activity, e.g.) typing

Question 19

The motor cortex: Broca’s area

Answer 19

Located in the motor association area

• Co-ordinates the muscles involved in speech generation
• In only one hemisphere

Question 20

The motor cortex

Frontal eye field

Answer 20

Located in the motor association area

-Co-ordinated muscles involved in eye movements

Question 21

Each of the 3 areas of the motor cortex (association area):

Answer 21

1. ) Contain “memory banks” for complex motor activities
2. ) Co-ordinate the movement of several muscle groups
3. ) Act via the primary motor cortex

Question 22

Damage to the primary motor cortex:

Answer 22

e. g.) stoke (ischaemic tissue damage)
- Paralyses the skeletal muscles controlled by the damaged area-voluntary movements only, not reflexive movement (which usually only involves the spinal cord not the motor cortex)

Question 23

Damage to the premotor cortex

Answer 23

Loss of motor skills programmed by the damaged region but discrete movements unhindered
e.g.) typing area damaged=unable to type quickly but able to make the same discrete movements-able to reprogram another set of premotor neurons (relearn the activity)

Question 24

The sensory cortex

Answer 24

The primary sensory and association areas are located in parietal, temporal and occipital lobes

• Concerned with the conscious awareness of sensation
• Somatosensory (general sensory) stimuli e.g.) touch, pain ect.
• Special sensory stimuli e.g.) vision, taste

Question 25

Sensory and association areas include:

Answer 25

- Primary somatosensory cortex - Visual cortex - Auditory cortec - Olfactory and gustatory cortex - Visceral sensory area - Vestibular (equilibrium) cortex - General interpretive are (Wernicke's area)

Question 26

The primary somatosensory cortex

Answer 26

Located in the post-central gyrus of the parietal lobes | -Information from one side of the body reaches the contalateral sensory cortex after passing through the thalamus

Question 27

The primary somatosensory cortex: Receives somatosensory information via multi-neuron sensory pathways from...

Answer 27

1. ) General sensory receptors in the skin (e.g. touch, pressure, vibration, pain, temperature) 2. ) Proprioceptors in skeletal muscles, joints and tendons (body position)

Question 28

Specific areas of the primary somatosensory cortex are devoted to analysing sensory information from specific body parts

Answer 28

- Stimulus destination indicates site of origin - The amount of sensory cortex devoted to a particular body region is related to that region's sensitivity (i. e. the more sensory receptors an area has"greater sensitivity"a larger area of the cortex required to analyse incoming information)

Question 29

The somatosensory association area

Answer 29

Located posterior to the primary somatosensory cortex in the parietal lobe -Interprets incoming sensory information by comparing it to stored memories of past sensory experiences

Question 30

Damage to the somatosensory association area...

Answer 30

Los the ability to identify objects by touch alone | -Need another sense such as visual information, to identify an object

Question 31

Special sensory cortices: Visual areas-Occipital lobes

Answer 31

``` Visual cortex -Receives impulses from the retinas -Damage: functional blindness visual association area -Interprets visual images -Damage: Failure to recognise objects ```

Question 32

Special sensory cortices: Auditory areas-Temporal lobes

Answer 32

``` Auditory cortex -Receives impulses from inner ear -Damage: deafness Auditory association area -Interprets auditory stimuli -Damage: failure to recognise what is heard ```

Question 33

Special sensory cortices: Olfactory cortex-Temporal lobe

Answer 33

Conscious awareness of odour

Question 34

Special sensory cortices: Gustatory cortex-Insula (deep to the temporal lobe)

Answer 34

Perception of taste stimuli

Question 35

Special sensory cortices: Visceral cortex-Insula

Answer 35

Perception of visceral sensations | e.g.) upset stomach, full bladder

Question 36

Special sensory cortices: Vestibular (equilibrium) cortex-insula

Answer 36

Awareness of balance

Question 37

General interpretive area: Wenicke's area

Answer 37

Generally in the left temporal lobe (same side as Broca's area) - Linked to Broca's area (motor speech area) - Integrates information from sensory, visual and auditory areas - Recognition and understanding of spoken and written language

Question 38

Damage to Wernicke's area

Answer 38

Affects ability to interpret visual and auditory information | i.e.) aphasia (inability to understand language or even speak, read and write)

Question 39

Multimodal association area

Answer 39

Located in the prefrontal cortex - Most complicated cortical area - Coordinates information from all association areas

Question 40

Multimodal association area is involved in...

Answer 40

intellect, complex learning abilities, recall and personality - Working memory-abstract ideas, judgement, reasoning, planning - Maturation associated with environmental interaction over time

Question 41

Cerebral white matter

Answer 41

Responsible for communication between hemispheres and between the cerebral cortex and other CNS areas -Predominantly made up of myelinated fibre tracts

Question 42

Cerebral white matter: Commissures

Answer 42

Connect the two hemispheres | e.g.) corpus callosum

Question 43

Cerebral white matter: Association fibres

Answer 43

Connect different parts of the same hemisphere

Question 44

Cerebral white matter: Projection fibres

Answer 44

Connect cerebral cortex with other CNS areas

Question 45

Cerebral basal nuclei

Answer 45

Concentration of gray matter (nuclei) deep within each cerebral hemisphere - Communicate with the motor areas of the cerebrum and cerebellum - Help to control the intensity of skeletal muscle movements executed by the primary motor cortex-dampen muscle activity to facilitate smooth movement

Question 46

Cerebral basal nuclei activity...

Answer 46

Regulated by the neurotransmitter dopamine (decreases basal nuclei activity) - Overactivity: Movement impaired, e.g.) Parkinson's disease - Under-activity: Excessive movement, e.g.) Huntington's disease

Question 47

The cerebrum summary

Answer 47

Largest part of the brain, divided into 2 hemispheres each with similar and distinct functions

Question 48

The cerebrum summary: functions of the cerebral cortex (gray matter)

Answer 48

- Conscious thought processes and intellectual functions - Controlling voluntary skeletal muscle activity - Localising and interpreting sensory input - Emotional processing - Memory processing and storage

Question 49

The cerebrum summary: functions of the white matter include

Answer 49

Communication via fibre tracts

Question 50

The cerebrum summary: functions of the basal nuclei

Answer 50

Control intensity of (dampen) skeletal muscle activity to facilitate smooth movement