Central Nervous System II

Question 1

What is the necessity of the CNS?

Answer 1

Maintenance of homeostasis

Question 2

How is the CNS supported?

Answer 2

Physical support and protection by bone - Skull (cranium) and vertebrae

Question 3

What are the membranes in the brain called and what are the 2 types?

Answer 3

Meninges - Cranial meninges and spinal meninges

Question 4

What do both the cranial and spinal meninges subdivided into?

Answer 4

Dura (hard) mater - Tough, fibrous, inelastic membrane (incases brain and runs down spine)
Arachnoid mater - Thin, transparent sheet, no space between dura
Pia mater - Tender, thin membrane, close to brain, separated from Arachnoid by CSF

Question 5

What is the cerebral spinal fluid (CSF)?

Answer 5

Clear watery fluid that bathes the CNS, fills cavities of brain/spine

Question 6

Describe the flow of CSF to the spinal cord

Answer 6

From lateral ventricles to third ventricle, cerebral aqueduct, fourth ventricle to central canal to spinal cord

Question 7

What are the ventricles lined with?

Answer 7

Epithelial cells - Ependymal cells which is secreted by choroid plexus

Question 8

Describe brain capillaries

Answer 8

No pores/clefts only tight junctions which are selectively permeable small highly lipid soluble material

Question 9

What is the importance of the blood brain barrier?

Answer 9

Brain stem controls vomiting reflex so detects toxic substances in blood causing vomiting to rid it

Question 10

Describe the function of the BBB

Answer 10

Protects brain/spinal cord from body
Protects CNS from foreign substances, diseases, immune cells. From hormones/NT in systemic circulation and from environmental fluctuations

Question 11

What does the CNS look like through an MRI/CAT scan?

Answer 11

Made up of grey and white matter

Question 12

What is the grey matter?

Answer 12

Cell bodies of neurons and solid mass of nerve fibres

They’re dense cells hence look grey

Question 13

What is the white matter?

Answer 13

Have no neuron cell bodies, made up of myelinated nerve fibres, high lipid content (fat) so looks white

Question 14

Describe the function of white matter in the CNS

Answer 14

Bundles of nerves that connect to cerebral cortex, along projection and association fibres

Question 15

Describe projection fibres in the CNS

Answer 15

Connect the cerebral cortex and spinal cord to both hemispheres of the brain (crosses over)

Question 16

Describe the association fibres in the CNS

Answer 16

Connect to areas of the cerebral cortex in the same hemisphere

Question 17

Describe commissural fibres

Answer 17

Connect the two hemispheres of the brain together via the pathway of the corpus callosum

Question 18

What are the 7 parts of the CNS?

Answer 18

Forebrain - Telencephalon and Diencephalon
Brain stem - Midbrain, pons, medulla oblongata
Cerebellum and spinal cord

Question 19

Describe the forebrain in detail

Answer 19

Telecephalon - Cerebrum: Cerebral cortex, subcortical cerebral nuclei
Diencephalon - Hypo, thalamus

Question 20

Describe the formation of the spinal cord

Answer 20

C1-8: Cervical vertebrae 
T1-12: Thoracic
L1-5: Lumbar
S1-5: Sacral
Co: Coccygeal

Question 21

Describe the function of the spinal cord

Answer 21

Provides 2 way conduction pathway to/from brain via asc/descenging tracts
Major reflex centre

Question 22

Describe the difference between the ascending and descending tracts

Answer 22

Ascending - Signal to brain

Descending - From brain to body

Question 23

What happens if damage occurs to the spinal cord?

Answer 23

Loss of motor/sensory function below site of injury

Question 24

Describe the pathway of signalling in the spinal nerve from skin to effectors

Answer 24

Sensory receptor from skin via afferent axon to dorsal horn, synapses to CNS then to motor neuron and exit via ventral horn through efferent axon via spinal nerve to effectors

Question 25

What is the front and back of the spine called?

Answer 25

Front - Ventral

Back - Dorsal

Question 26

Describe the cerebellum (appearance)

Answer 26

Bilaterally symmetrical

Made up of cortex and nuclei

Question 27

Describe the function of the cerebellum

Answer 27

Motor coord, balance, posture
Coord of eye/body movements
Subconscious movements
Motor learning of repeated tasks (eg cycling)

Question 28

Describe the connections of the brainstem

Answer 28

Connects forebrain/cerebellum to spinal cord

Midbrain to forebrain, Pons to cerebellum, Medulla to spinal cord

Question 29

Describe the function of the brainstem

Answer 29

Autonomic function - Control heart rate, respiration, bp, pupil reflex

Question 30

Describe the hypothalamus of the diencephalon

Answer 30

Homeostatic control (autonomic/endocrine) eg thirst, hunger, h2o balance, body temp, circadium rhythm, emotions

Question 31

Describe the thalamus of the diencephalon

Answer 31

Integrating centre of sensory/motor impulses to cortex

Key in awareness

Question 32

Describe the lobes of the brain and their functions

Answer 32

Frontal: Decision/problem making, motor
Parietal: Somatosensory info
Temporal: Memory, emotions, audio, language
Occipital: Vision

Question 33

What is the central and lateral sulcus?

Answer 33

Central sulcus separates frontal and parietal lobes

Lateral sulcus separates the frontal/parietal from temporal lobe

Question 34

Describe other nuclei which are part of the cerebrum

Answer 34

Nuclei below cerebral cortex - Basal ganglia, many nuclei of making up caudate, putamen and globus pallidus (together striatum)

Question 35

Describe the function of the striatum

Answer 35

Info to/from cortex via thalamus, vital for movement

Question 36

What could happen if damage occurs to parts of the basal ganglia?

Answer 36

Cause conditions such as parkinson’s/huntington’s disease which affect this region

Question 37

Describe another system within the cerebrum

Answer 37

Limbic system - Links conscious function of cerebral cortex to unconscious/autonomic function of brain

Question 38

Describe the different parts of the limbic system and their functions

Answer 38

Amygdala: Aggression, fear, emotions
Hippocampus: STM
Fornix: Connect hippo to hypo