14. Nervous System II Flashcards
What does the central nervous system consist of?
The brain and the spinal cord
What are the connective tissue layers that cover the brain and spinal cord?
(Overall name, and the 3 specific layers)
The Meninges
1) Dura Mater - tough fibrous outer later
2) Arachnoid mater - middle layer of collagen and elastic fibres
3) Pia mater - thin inner most layer containing blood vessels
What are the two gaps between the meninges called and where are they located?
1) Subdural space between the dura mater and the arachnoid mater.
2) Subarachnoid space between the arachnoid mater and pia mater
What 2 haemorrhages can occur in the spaces between the meninges and how do they differ?
Subdural haematoma - as this is venous blood is develops slowly
Subarachnoid haemorrhage - arterial bleed so rapid (feels like being hit in the back of the head - an explosive headache).
What is cerebrospinal fluid (CSF)?
A clear liquid that protects the brain and spinal cord from mechanical and immunological trauma.
Where can you find cerebrospinal fluid (CSF)?
Subarachnoid space
Ventricles (cavities) of the brain
Central canal of the spinal cord
What cells make cerebrospinal fluid and how much of it?
Ependymal cells make 500ml / day
List 4 functions of the cerebrospinal fluid.
1) Supports and protects the brain and spinal cord acting as a shock absorber.
2) Maintains uniform pressure around the brain
3) Keeps brain and spinal cord moist
4) Circulates nutrients and waste
5) Provides optimal chemical environment for nerve signalling
What arteries supply blood to the brain?
Vertebral & carotid arteries
What is the purpose of the blood brain barrier?
To protect the brain from toxins, harmful substances and bacteria that enter the bloodstream.
Describe how the blood brain barrier works.
Astrocytes maintains tightness of the capillaries and the junctions between the cells.
What can pass through the blood brain barrier? (4)
- Lipid soluble substances
- Glucose
- Gases (eg oxygen and carbon dioxide)
- Ions
Name the 4 main parts of the brain
1) Brain steam
2) Diencephalon
3) Cerebrum
4) Cerebellum
Of the 3 sections of the brainstem, provide:
- their name
- key functions
- the nerves they contain
Medulla oblongata
- contains respiratory & cardiac centres
- controls reflexes such as vomiting
- contains 4 cranial nerves (9-12)
- contains motor tracts
Pons
- helps control breathing
- contains 6 cranial nerves (5-8)
- relays motor tracts
Midbrain
- controls subconscious muscle activities
- eye reflexes and tracking
- 2 cranial nerves (3-4)
Of the 3 sections of the diencephalon, provide:
- their name
- key functions
Thalamus:
- Major relay centre of sensory information
Epithalamus:
- Connects limbic system to other parts of the brain
- Contains the pineal gland
Hypothalamus:
- Hormone regulation and homeostasis
- Controls ANS
- Controls body temperature
- Regulates emotions and behavioural patterns
Describe the main functions of the cerebellum
- Maintenance of posture and balance
- Coordinating complex movements
- Correction of errors during ongoing movement
What can damage the cerebellum?
- Chronic alcohol abuse
- Coeliac’s disease
- Thiamine (Vit B1) deficiency
What are the 2 main functions of the cerebrum?
- Sensory perception
- Motor control of skeletal muscles
What are the 4 areas of the cerebrum and name 1 function for each?
- Frontal lobe - motor skills
- Temporal lobe - hearing
- Parietal lobe - sensory interpretation
- Occipital lobe - vision
What is the limbic system?
It’s the area of the brain that is active with different emotions.
Name 3 key structures found in the limbic system.
1) Hypothalamus
2) Hippocampus
3) Amygdala
How much of the cardiac output does the brain receive?
20% / 750ml per minute
What is the meeting point of the carotid and vertebral arteries called?
Circle of Willis
What’s the 1st cranial nerve?
Where is it located?
What is its function?
Is it sensory or motor?
Olfactory nerve
Located in cerebrum
Sense of smell
Sensory
What’s the 2nd cranial nerve?
Where is it located?
What is its function?
Is it sensory or motor?
Optic nerve
Cerebrum
Vision
Sensory
What’s the 3rd cranial nerve?
Where is it located?
What is its function?
Is it sensory or motor?
Oculomotor
Midbrain
Eye movement, eyelids, pupil size
Motor
What’s the 4th cranial nerve?
Where is it located?
What is its function?
Is it sensory or motor?
Trochlear
Midbrain
Eye movement
Motor
What’s the 5th cranial nerve?
Where is it located?
What is its function?
Is it sensory or motor?
Trigeminal
Pons
Facial Sensations, chewing
Sensory and motor