Nervous system physiology (2) The Brain Flashcards
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What is the function of CSF?
- This is the clear colourless liquid that acts to protect the brain and spinal cord from injury
- It transports oxygen and glucose from the blood to the neurons and neuroganglia.
- It provides mechanical protection to the brain and spinal cord by acting as a shock absorber, in a sense the brain ‘floats’ within the cranial cavity.
CSF provides the optimum chemical environment for neuronal signalling even very slight changes in the ionic environment can have drastic effects on nerve function.
Because CSF circulates, it allows the exchange of nutrients and waste products between the blood and nervous tissue.
What is the total volume of CSF?
The total volume is ~ 80-150 mL
What does CSF contain?
CSF contains glucose proteins, lactic acid, urea, Na+, K+, Ca2+, Mg2+, Cl-, HCO3-, it also contains some white blood cells.
Label this image and where does the CSF flow?
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What/where is the CSF made?
What’s it made from and how?
- Networks of capillaries in the walls of the ventricles, these are covered with ependymal cells it is these which make CSF from the blood plasma by filtration and secretion and forms the blood-cerebralspinal fluid barrier.
- This permits certain substances to enter CSF whilst blocking other potentially harmful substances.
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What does the mid brain do?
This area of the brain relays motor output from the cerebral cortex to the pons. It relays sensory input from the spinal cord to the thalamus
What do the superior and inferior colliculi do?
The superior colliculi coordinates the movement of your eyes in response to visual stimuli.
The inferior colliculi coordinates head and trunk in response to auditory stimuli.
What does the substantia nigra and red nucleus do?
Most of the substantia nigra and red nucleus are concerned with the control of movement.
The substantia nigra is the area of the brain which produces the neurotransmitter dopamine.
Lack of dopamine results in Parkinson’s disease.
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What does the pons do?
This area relays impulses from one side of the cerebellum to the other and between the medulla and mid brain.
With the medulla it is also important in the control breathing.
What does the medulla oblongata do?
Relays sensory input and motor output between the brain and spinal cord there seems to be a function in arousal and consciousness.
Regulates heartbeat blood vessel diameter and breathing, also vomiting, cough reflex, swallowing and sneezing.
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What does the cerebellum do?
- Integration of sensory perception and motor output
- Constant feedback on body position allows fine movement, lesions do not result in paralysis but problems with fine motor movement, posture and motor learning
- Cognitive function, attention, processing language, music and other temporal stimuli
What does the diencephalon comprise of?
Thalamus
Hypothalamus
Epithalamus
Ventral Thalamus
Third ventricle
What does the thalamus do?
•Provides crude perception of pain heat etc, it is also involved in movement planning and control.
What does the hypothalamus do?
- Controls and integrates the autonomic nervous system and pituitary gland.
- It regulates emotion and behaviour.
- It regulates eating and drinking and maintains sleep patterns.
- It has endocrine function as it produces the hormones oxytocin and ADH.
What is the epithalamus?
Consists of the pineal gland which secretes melatonin and the habenular nuclei, the function of this area is poorly understood.
What is the cerebrum, physical properties?
Largest part of brain, divided into two halves, the right and left cerebral hemispheres
The folds and convolutions of the surface of the cerebral hemispheres vastly increase the effective surface area of the brain.
Each ridge is called a gyrus and each groove between ridges is called a sulcus. A deep sulcus is referred to as a fissure.
What is the cerbrum responsible for?
- Perception of sensory information, motor control
- Complex cognitive functions such as memory intelligence and personality
- Basal ganglia regulate the muscle tone of your body and coordinate gross automatic muscle movements
- The limbic system seems to be involved in the emotional aspects related to survival ‘FEAR’