The Human Brain Flashcards
What are the 4 ventricles of the brain?
-1 and 2 are the cerebrum which are interconnected
-3 is diencephalon
-4 brainstem
What does the nervous system develop from?
a hollow neural tube
what are the three areas of the brain of an embryo at 1 month
-mid brain
-hindbrain
-forebrain / diencephalon
what are the 5 areas of the brain of an embryo at 5 weeks
-spinal cord
-telencephalon
-diencephalon (forebrain)
-mesencephalon
-metencephalon
what are the 7 areas of the brain in a baby when its born?
-cerebrum
-diencephalon (forebrain)
-midbrain
-pons
-medulla oblongata
-cerebellum
-spinal cord
how is the brain protected?
-skin
-cranium
-meningeal sheaths
-cerebrospinal fluid
-highly selective blood brain barrier
how is the cerebrospinal fluid protective?
by acting as a shock absorber as it flows between the 4 ventricles, the SC, central canal and the meningeal layers, its continually circulated and replaced
what is the condition caused by excess CSF called?
hydrocephalus
how is the blood brain barrier protective?
as its highly selective by limits exchange of materials between blood & brain and Permeable to lipid-soluble substances (O2, CO2, alcohol), small water-soluble substances diffuse
what is the cerebrum and what are its two main structures?
it is the central processing centre divided into two hemispheres connected via the corpus callosum which contains 300 neuronal axons that lie transversely and allow constant info exchange between the two hemispheres
the two main structures are the cerebral cortex and the basal nuclei
what do the infolds of the cerebrum have?
gyri and sulci
what does each hemisphere of the cerebrum contain
grey matter (neuronal cell bodies, dendrites and glial cells) which has 40% of the tissue and the cerebral cortex
what does the thick central core of the cerebrum contain?
white matter which consists of tracts of myelinated axons and makes up 60% of the tissue with tracts connecting
-gyri - association
-hemispheres - commissural
-cerebrum to lower CNS - projection
What are the three main brain regions?
-brain stem
-cerebellum
-forebrain
what does the brain stem contain?
-mid brain
-pons
-medulla
what does the forebrain contain?
-diencephalon (hypothalamus and thalamus)
-basal nuclei
-cerebral cortex
what are the 4 lobes that each hemisphere of the cerebral cortex divides into and what are they each for?
-frontal lobe: speech and motor cortex
-parietal lobe: speech, tatse, reading, somatosensory association area
-occipital lobe: visual association area so vision
-temporal lobe: auditory association area - smell and hearing
be able to label the parts of the cerebral cortex and their functions
check ss
in the cerberal cortex, what are the following higher function areas for?
-broca’s area is for speech
-wernicke’s area if for understanding
-association cortices is interconnected by cerebral white matter nerve fibres so integrate diverse info
-primary auditory cortex for hearing
-primary visual cortex for vision
what is the somatosensory cortex for?
-site of initial processing and perception of body sensations and proprioception with info recieved from the cns and and
what is the primary motor cortex for?
the voluntary control over skeletal muscle movement and stimulation of regions produces movement in opposite sides of the body as the neuronal tracts cross over
what is a motor homunculi?
a map of brain areas dedicated to motor processing for different anatomical divisions
what are the three higher motor cortex areas?
-supplementary motor cortex
-posterior parietal motor cortex
-premotor cortex
what is the cerebellum for?
to initiate, plan and time certain movements by sending input top the decision maker regions
give the pathway from sensory input to motor output
- sensory input
- primary sensory areas being somatosensory, primary visual, primary auditory cortexes
- higher sensory areas
- association areas
- higher motor areas
6.primary motor cortex - motor output
what does the limbic system of the brain consist (make sure you known where) of and what are it’s four main roles?
contains:
-cerebral cortex - limbic association centre
-hypothalamus - homeostasis
-hippocampus - memory
-amygdala - fear
roles:
-survival behaviour: attack, defence, search for food
-subjective emotional feelings: fear, anger, joy, sadness
-emotional expression: pleasure, laughing, crying
-memory and learning
what does the basal nuclei of the brain consist of (be able to label these) and what does it do?
contains:
-caudate nuclei
-putamen
-globus pallidus
-nucleus accumbens
it works with motor cortex to suppress unwanted or unnecessary movement. this can help maintain balance and posture
what does the forebrain consist of? what does it do? what is it a relay centre for?
the thalamus and the hypothalamus. it integrates conscious and unconscious sensory info and motor commands. contains auditory and visual startle reflex centres
relay centre for
-sensory info
-motor responses from the cerebrum
what are the 5 functions of the thalamus and what does it use to project information to the cerebral cortex?
-relays sensory input to the cortex
-screens and routes input to apt somatosensory cortex regions
-crude recognition of senstions like pressure pain and temp
-translates info to make it readable by cortex
-directs attention stimuli e.g. sleep, wakefulness
what does the hypothalamus link between and what does it regulate/
-links between ANS and endocrine system via the pituitary gland
regulates:
-blood pressure, digestive system, heart rate and body temp
-thist and urine output via osmoregulation
-food intake
-sleep/wake cycle
-emotions and behaviour
-endocrine control
what are the three functions of the cerebellum? what are its 3 functional regions?
-maintenance of muscle tone, posture and balance
-fine tunes conscious and unconscious movements
-in proprioception to sense movement and body position
functional regions
-vestibulo-
-spino-
-cerebro-
what are the three regions of the brain stem and what are the its functions
regions:
-midbrain
-pons
-medulla oblongata
functions:
-regulate vital functions like heartrate
-muscle reflex regulation
-connection between cerebrum and spinal cord
-attachment point for 10 cranial nerves
learn the 12 cranial nerves, their composition and their functions off of the table
check ss
what is the reticular activating system and what are its roles?
interconnected neurones throughout the brain stem and into the thalamus and receives and integrates all sensory and synaptic input. the ascending fibres go to the cortex and descending fibres activate the RAS
-has roles in arousal, sleep, alertness, emotions, motivation and selective attention
what does the pons allow for information transfer between?
from the brain to the SC and from the pons to the cerebellum
what respiratory reflexes does the pons control?
-start of apneustic and pneumotaxic reflexes
-apneustic centre triggers breathing
-pneumotaxic centre triggers exhalation
what are the reflex centres that the medulla oblongata contains?
-coughing
-sneezing
-swallowing
what are the functions of the medulla oblongata?
-control vital involuntary actions like heart rate and blood pressure
-transfer motor impulses from brain to PNS
-to connect the brain to the SC
