The brain 13 Flashcards
what does the brains blood supply require?
- 20% of bodys oxygen supply - 4 mins lack of oxygen equals permanent damage.
*requires continuous glucose supply.
the brains blood supply is protected by a blood brain barrier, what does it allow through the barrier?
It allows lipid soluble materials - O2, CO2 , alcohol, anaesthetic agents but controls entry of everything else.
what creates the brains blood supply?
tight capillaries and glial cells - astrocytes.
what does the brain stem contain?
medulla oblongata (small bump), pons (larger bump), midbrain.
what does the brain stem connect with?
Spinal chord.
what is the medulla oblongata (part of brain stem) made up of?
White matter extending between spinal cord and other parts of brain.
medulla oblongata contains several nuclei/clusters of cell bodies, what are the 3 vital reflex centres?
Cardiovascular centre (heart rate),
medullary rhythmicity area (respiratory rhythm)
and vasomotor (vasoconstriction)
other sensory, reflex motor areas eg sneezing, vomiting.
What does pons (part of brain stem) do ?
connects spinal chord with the brain - links one part of the brain with another by way of tracts/ groups of nerve axons.
Do nerve tracts cross at the pons (brain stem)?
Yes, nerves supplying left side of body cross to right side of brain and from right side of body to left side of brain.
what does the midbrain (brain stem) connect together?
Connect pons to diencephalon.
what does the midbrain do? (brain stem)
- conveys motor impulses from cerebrum to cerebellum and spinal cord.
*conveys sensory impulses from spinal cord to thalamus
what does the midbrain contain?
contains the substantial nigra - areas affects by Parkinson’s disease - dopamine.
What are the 4 major areas of the brain?
Brain stem, diencephalon, cerebrum, cerebellum.
Diencephalon is found above the brain stem, what is included?
Thalamus, hypothalamus, and pineal gland - melatonin
what does the thalamus (diencephalon) do?
transmits motor information from cerebellum and basal nuclei to cerebrum.
Hypothalamus (important for homeostasis), has 6 functions what are they?
1) control of ANS-regulation of many activities.
2) control of pituitary and hormone production.
3) regulation of emotional and behaviour patterns.
4) regulation of eating and drinking
5) control of body temperature.
6)regulation of circadian rhythms and states of consciousness.
what does the pineal gland (diencephalon) do ?
Secretes melatonin which promotes sleep.
cerebrum is at the top of brain and largest part, what is it made up of?
surface covered with grey matter, cerebral cortex
beneath is cerebral white matter
explain the cerebrum structure.
-cerebral cortex - grey matter/cell bodies
-internal white matter
-surface folds - gyri/gyrus
- grooves between-sulci/sulcus
-longitudinal fissure- dvivides into left and right hemispheres
- connected by corpus callosum.
what do motor areas of the brain do?
initiate movements.
what do sensory areas of the brain do?
receive input and responsible for perception.
what do associative areas of the brain do?
complex integration eg memory, emotion, reasoning.
what are the four cerebral hemisphere lobes ?
frontal, parietal, temporal, occipital
what is the right side of cerebrum important for?
spatial and pattern recognition and emotional content.
what is the left side of cerebrum important for?
spoken and written language, numerical and scientific skills and reasoning.
cerebellum is found back of the brain, what does it mean?
means little brain.
what is the cerebellum made up of?
2 cerebellar hemispheres - posterior to medulla and pons, below cerebrum.
cerebellar cortex - grey matter
interior - white matter and nuclei
attached to brain stem via cerebellar peduncles.
what is the function of the cerebellar?
receives range of sensory input.
coordinates skeletal muscles - regulates posture and balance, maintains muscle tone.
Functions noticeable after excessive alcohol intake, ataxia, lack of muscle co-ordination.
what happens in ageing of the brain?
rapid growth first few years,
age increases development of dendritic branches and synaptic contacts,
there is a decline in brain mass from early adulthood onwards.
