NB2 Flashcards
How many cortexes are there in the brain
- Motor cortex (in frontal lobe)
- Somatic motor association area - Sensory cortex (in parietal lobe)
- Somatic sensory association area - Visual cortex (in occipital lobe)
- Primary visual cortex (posterior part of lobe) + Visual association area (anterior part of lobe) - Gustatory cortex
- Olfactory cortex
- connects smell with memory - Auditory cortex
- Primary auditory cortex (superiorly) + Auditory association area (inferiorly)
Efferent (motor) nerves is a 2 neurone pathway
- The two neurone pathway is upper motor neurone and lower motor neurone
- Upper motor neurone starts in the cerebral motor cortex (pre-central gyrus) to brainstem/spinal cord
- Lower motor neurone goes from brainstem cranial nerve motor nucleus or from cord to muscle
Motor pathway definitions
- Pyramidal system upper motor neurone starts in the cerebral cortex (pre-central gyrus). They pass through the pyramids of the medulla.
- Conscious movement. - Extrapyramidal system upper motor neurone starts in other brain centre nuclei (basal ganglia). They do not pass through the pyramids of the medulla.
- Fine tune movement
What is the cerebellum responsible for
Balance, tone, posture & co-ordination and planning movement
What is the basal ganglia
It is a diffuse set of nuclei responsible for allowing/stopping movements to happen
(nucleus accumbens, caudate, putamen, globus pallidus, subthalamic nucleus, substantia nigra)
Fine tune movement
Lentiform nucleus = Putamen + Globus pallidus
What is the thalamus for
- Sensory relay station in the brain
- All general sensory information goes through the thalamus
- Located on either side of the third ventricle
Major sensory pathways
Afferent nerves in cranial and spinal nerve
General senses: 3 neurones
2 sensation type :
1) Touch/Proprioception
- Dorsal columns
- Decussates in medulla
2) Pain & Temperature
- Spinothalamic tract
- Decussates immediately
What is the limbic lobe and its function
(Cingulate gyrus, hippocampal formation and amyglada - deep in temporal lobe)
- Emotional aspects of behaviour and memory
- “Societal homeostasis” based on external inputs at a basic/survival level
How many ventricles are there in the brain
4
2 Lateral; 1 Third Ventricle; 1 Fourth Ventricle
What are the lateral ventricles for
Cavities of cerebral hemispheres filled with CSF
Flow of CSF
CSF flows from lateral ventricle through interventricular foramen of Monro to third ventricle
-third ventricle is cavity of diencephalon
Third ventricle and fourth ventricle is joined together by cerebral aqueduct of Sylvius
CSF then flows to subarachnoid space through foramina of Lushka (laterally) and foramina of Magendie (posteriorly)
Anatomy from 4th ventricle
Posteriorly - foramina of Magendie
Laterally - foramina of Lushka
What is hydrocephalus
- Too much CSF will push the skull out
- Only occur in babies where bones are not fused yet
- In adults, there is an increase in intracranial pressure
What is the term for the gaps before the bones are fused
Fontanelle
Cranial nerve 1
Olfactory nerve
-smell
Cranial nerve 2
Optic nerve
-vision
Cranial nerve 3, 4, 6
3: Oculomotor nerve
4: Trochlear nerve
6: Abducens nerve
- eye movement
Cranial nerve 5
Trigeminal nerve
-facial and scalp sensation, mandibular movements (chewing)
Cranial nerve 7
Facial nerve
-facial expression
Cranial nerve 8
Vestibulocochlear nerve
-hearing, balance
Cranial nerve 9, 10
9: Glossopharyngeal nerve
10: Vagus nerve
- swallowing, phonation
Cranial nerve 11
Accessory nerve
-neck and head movements
Cranial nerve 12
Hypoglossal nerve
-tongue movement
What is so special about the spinal cord
Dura and arachnoid mater is stuck together
There is no subdural space in the spinal cord
What is Cauda Equina Syndrome (CES)
- bundle of nerves below the end of the spinal cord known as the cauda equina is damaged.
- spray of nerves that come off the bottom of the spinal cord and activates bladder, bowel, sexual organs and legs
- when nerves are compressed or damaged
- causes lower back pain (due to ruptured disc), pain that radiates down the leg, and loss of bowel or bladder control
What causes CES
- back/spine problems such as slipped disc
- tumours near the spine
- injuries, trauma
Warning signs of CES
“SPINE”
S: Saddle Anaesthesia
-Weakness, tingling or numbness in ‘saddle’ region (supplied by pudendal nerve - S2,3,4)
P: Pain
-Pain, weakness tingling or numbness in your lower back, backs of thighs, lower legs and feet
I: Incontinence
-Loss of control, urgency or finding it hard to pee or poo or any strange sensation when peeing or pooing
N: Numbness
- Numbness in your lower back, back of thighs, lower legs and feet
- Loss of feeling around groin during sex
E: Emergency
