The brain and cranial nerves Flashcards
Week 4
What does the brain stem consist of?
The continuation of the spinal cord and consists of the medulla oblongata, pons and midbrain
What is the diencephalon?
It consists of the hypothalamus, the thalamus and the epithalamus
Name the subcortical structures found in the brain
The diencephalon, pituitary gland, limbic structures and the basal ganglia
What is the basil ganglia?
A group of subcortical structures that play a crucial role in motor functions, executive functions and emotional behaviour
What occurs in the cerebral cortex?
Perception, thought, imagination, judgment, and decision making
What is the role of the thalamus?
it is a “relay station” of all incoming motor and sensory information - hearing, taste, sight and touch (but not smell) - from your body to your brain
What is the role of the hypothalamus?
Homeostasis - keeping the body in a stable / balanced state through the release / inhibition of hormones
What is the role of the brain stem?
The brainstem is the base of the brain that connects it to the spinal cord and controls vital functions like breathing and heartbeat, it consists of the midbrain, the pons, and the medulla oblongata
What executive functions are associated with greater frontal lobes?
Self-control, planning, reasoning, and abstract thought
How much does the cerebrum weigh on average?
1300g
How many neurons are there in the cerebrum on average?
Around 100 billion
What is the dura mater?
It is a thick protective membrane that is made up of dense irregular connective tissue and surrounds the brain and spinal cord
Describe the structure of cerebral grey matter
The folds are called gyri, the deepest of which are known as fissures; the shallower grooves between folds are called sulci, the grey matter is only 5-6mm thick but accounts for 80% of the weight of the cerebrum
Which fissure splits the cerebrum into right and left hemispheres?
The longitudinal fissure
What divides the anterior frontal lobe from the more posteriorly situated parietal lobe?
The central sulcus
How long could it take for signs and symptoms of inter cranial pressure (ICP) to set in?
Up to 12 hours
What is the limbic system?
It does not represent any one part of the brain, is a functional system composed of parts of the cerebral cortex, diencephalon, and midbrain
Name and point to the four lobes of the cerebrum
Frontal - forehead
Parietal - top of head
Temporal - sides round ears
Occipital - right at bottom / back of head
What kind of behaviour could be induced by damage to the frontal lobe?
Combativeness, abusive attitude and inappropriate sexual activity
What are Brodmann’s areas in the cerebrum?
They are numbered regions of cortex that have been “mapped” to specific cognitive functions
What do motor areas of cerebral cortex control?
Voluntary movements
Wernicke’s area?
Located in the parietal and temporal lobe, it helps with understanding speech as well as usage of correct words to express specific thoughts
Broca’s speech area?
Located in the frontal lobe, It helps with motor movements required to produce speech
What is the somatosensory system?
It consists of receptors, neurons, and brain regions (somatosensory cortex) that process and interpret signals from different parts of the body
Examples of somatic sensations:
Touch, pressure, vibration, itch, tickle, temperature (coldness and warmth), pain, and proprioception (joint and muscle position / balance)
In which lobe do most strokes occur and why?
The parietal lobe - it is supplied by large arteries
Where in the cerebrum is the primary motor area located?
The precentral gyrus of the frontal lobe
Where is the primary visual area in the cerebrum located?
The posterior tip of the occipital lobe mainly on the medial surface
Where is the primary gustatory (taste) area located?
Just inferior to the primary somatosensory area
Where is the primary auditory area located?
In the the superior part of the temporal lobe
Where is the primary olfactory area located?
In the inferior medial temporal lobe
What does the cerebral white matter primarily consist of?
Myelinated axons
What are the three types of myelinated axon tracts called?
- Association tracts
- Commissural tracts
- Projection tracts
Describe the role of association tracts
They contain axons that conduct nerve impulses between gyri in the same hemisphere
Describe the role of commissural tracts
They conduct nerve impulses between corresponding gyri from one hemisphere to another
Describe the role of projection tracts
They convey impulses to lower parts of the CNS (thalamus, brain stem, or spinal cord) or visa versa
What is the corpus callosum?
It is one of the three important groups of commissural tracts – it is a thick band of axons that connects corresponding areas of the two hemispheres
What are the three basal nuclei, and what do they do?
… they are conspicuous centres of cell bodies deep in the cortex, they also help initiate and terminate movements, suppress unwanted movements, regulate muscle tone and control subconscious contractions of skeletal muscles
What are the three integrated brain systems?
- Reptilian brain
- Mammalian brain
- Cerebral cortex
What is the medulla oblongata?
It is located in the brainstem and is responsible for regulating…
What is the pons varolii?
Its is directly superior to the medulla and anterior to the cerebellum, it acts as a bridge connecting the spinal cord to the brain
Cerebellum?
Mid brain?
What is the role of the reticular formation?
The RAS functions to maintain consciousness, a state of wakefulness in which an individual is fully alert, aware, and orientated
What is the cerebellum?
It is the “little brain”, located inferior to the cerebrum and posterior to the brain stem; it compares intended movements with what is happening with skeletal muscles, and regulates posture, equilibrium, and balance
Cranial meninges - three…
Protect the brain, dura mater, arachnoid mater, pia mater…
How much of the bodies blood supply goes to the brain?
Around 20%
Which arteries supply blood to the brain?
Anteriorly, it’s the internal carotid arteries; posteriorly, it’s the vertebral arteries
What is the role of the internal jugular veins?
Venous return of blood from the brain
Blood brain barrier…
RESEARCH
What is the role of cerebral spinal fluid (CSF)?…
Production and flow of CSF
12 CRANIAL NERVES
MAKE MIND MAP
- Name them and how to check for damage
What is the blood brain barrier?
