MACROANATOMY Flashcards
How is post mortem histology beneficial?
allows researchers and continues to examine the brains of deceased patients
why is it carried out?
to find out exactly how or why the person died especially if it was unexpected or if there is a public health concern
What is EEG
- electroencephalogram - a non invasive technique
- electrodes on scalp to monitor electrical activity in the brain
- monitors and helps diagnose conditions that effect the brain (seizures suffered by patients with epilepsy)
MRI?
magnetic resonance imaging
what does it do?
- allows to see brain and specific regions in detail - ultra high resolution
- allows to reconstruct brain layers from full head to back of head
what can MRI detect when preformed live?
cysts, tumours, bleeding, swelling and developmental and structural abnormalities
Whats is functional MRI
used to infer brain activity by measuring changes in blood flow - research done by listening to music (shown a difference especially when a person is listening to their favourite music)
brain is divided into 4 parts
- Forebrain
- Brain stem
- Cerebellum
What is the forebrain split into?
- Telencephalon (cerebrum)
- cerebral cortex- frontal lobe
- temporal lobe
- parietal lobe
- occipital lobe
- subcortical structures
- hippocampus
- basal ganglia
- Diencephalon
- thalamus
- hypothalamus
What is the brainstem divided into?
- midbrain
- pons
- medulla oblongata
what are bumps in the brain called
gyri
what are grooves called in the brain
sulci
what are deep grooves called in the brain
fissures
central sulcus divides what two gyrae and the neurones are involved in?
- precentral gyrus - involuntary movement
- postcentral gyrus - control of somatic sensation e.g. touch
what are the neurones in the superior temporal gyrus involved in?
hearing
what doe lateral (Sylvian) fissure separate?
superior temporal from the post central and precentral gyrae
what is the largest part of the forebrain?
cerebrum
what parts do cerebrum contain
- cerebral cortex
- subcortical structures
what are the structures in the cerebral cortex
- frontal lobe
- parietal lobe
- temporal lobe
- occipital lobe
what is the frontal lobe responsible for in the cerebral cortex?
- control of voluntary movement
- control of behaviour
- attention, planning and decision making
- motivation and emotional regulation
‘home of our personality’
what is the parietal lobe responsible for
- sensory processing and interpretation
- proprioception (equilibrium and balance of body)
what is the temporal lobe responsible for?
- auditory processing and interpretation
- memory (e.g. formation of long-term memories)
what is the occipital lobe part of?
visual processing and interpretation (e.g. distance and depth perception, colour, object and face recognition)
what are the subcortical structures?
- hippocampus
- basal ganglia
what is the hippocampus?
a region of the cerebral cortex embedded deep within the temporal lobe
what is its function
learning
memory formation and retrieval
mediates Hypothalamus pituitary adrenal axis
what does hippocampal dysfunction cause?
anterograde amnesia - unable to create new memories
retrograde amnesia - generally unable to recall past memories
what are the different parts of the basal ganglia
- caudate
- putamen
- globus pallidus
What is the function of the basal ganglia?
regulating movement (initiation and maintenance of meobement, inhibiting antagonist movements)
What does damage to the basal ganglia cause?
Movement disorder - Parkinsons/Huntingtons
What occurs in the Huntington’s disease?
degeneration of GABA neurones in the cuadate and putamen lead to characteristic motor problems such as involuntary jerking of the limbs that is seen in huntigntons disease
What is the Diencephalon
a division of the forebrain situated between the cerebrum and midbrain - compromises the thalamus and hypothalamus
What is above the thalamus?
structures filled with cerebrospinal fluid shaped directly above the thalamus - compromised of large collection of different nuclei - each serving a unique function
What is the thalamus?
large collection of nuclei located in the dorsal part of the diencephalon
What is the function of the thalamus?
- relay between sensory and motor systems and the cerebral cortex
- regulate arousal and pain, mood, motivation and cognitive function
What occurs if changes in organisation of thalamic connectivity?
Synaesthesia - can be innate, based, inborn or natural or can be a consequence of damage to the thalamus
What is synaesthesia?
blending of information streams, ‘hearing colour’ ‘feeling sounds’
What is the hypothalamus?
small, almond-sized collection of nuclei located directly above the brainstem between cerebral cortex and midbrain
What is the function of the hypothalamus?
- smaller collection of nuclei with various functions
- homeostatic, reproductive and other diverse functions ‘fight or flight’
- fight or flight involves the hypothalamus-pituitary-adrenal (HPA) axis -> cortisol and adrenaline release
What occurs due to hypothalamic dysfunction?
hypothyroidism - underproduction and release of thyroids
hyperthyroidism - excessive release of thyroid hormones
What does the brainstem do?
connect brain to the diencephalon, its between diencephalon and spinal cord
What is the function of the midbrain?
include control of eye movements, auditory and visual processing
What is the function of pons
relay of motor information from cerebral hemispheres to the medulla, spinal cord and the cerebellum
What is the function of medulla oblongata
- cardiovascular and respiratory homeostasis
- reflexive actions including vommiting, swallowing, coughing and sneezing
What is ‘brainstem dead’
unable to regain consiosness or breath without the support of an artificial life support machine
- loss of blood circulation to all brainstem regions
What is locked in syndrome
- awake and conscious but no means of producing speech, limb or facial movements
- loss of blood circulation to pons
What is the cerebellum
‘little brain’ prominent hindbrain structure - it accounts for approximately 10% of the human brain volume
What is the function of the cerebellum
- does not initiate movement but detects differences in motor error between and intended movement and the actual movement
- aids the motor cortex to produce precise and coordinated movement
Where is the spinal cord?
within the vertebral column, with spinal nerves (part of peripheral nervous system) communicating with the cord via notches between the vertabrae
Where are the cervical vertebrae and names?
NECK
C1-C7
Where are the thoracic vertebrae and names?
RIBS
T1-T12
where are the lumbar vertebrae and names?
LOWER BACK
L1-L5
where are the sacral vertebrae and names?
PELVIC AREA
S1-S5
What is the difference between spinal cord and spinal column?
spinal cord does not grow after birth whereas spinal column does
What is the dorsal root?
describes bundle of sensory neurones axons that carry sensory information into spinal cord
What is ventral root
describes a bundle of motor neurone axons that carry information away from the spinal cord to striates muscle
What is grey matter
compromised of neuronal cell bodies divided into horns
what is white matter
compromised of axon bundles divided into columns
- almost forms thick shell around grey matter
What is the function of spinal cord?
- contains motor neurone that innervate skeletal muscle and allow for movement as well as motor tracts that carry information for motor movement down from the brain
- spinal cord also receives sensory information from periphery and contains pathways by which that sensory information is transmitted to the brain
How does reflex movements occur
sensory inputs, independent from the brain, accounts for reflex movements such as knee jerk reflex which involves two neurones, one sensory and one motor
- via different pathways, spinal cord allows both complex and simple motor movements
- simple being reflex
What Is tetraplegia?
full or partial loss of sensation and movement in all four limbs and torso
- caused by damage in cervical C1-C7 area
What is PARAPLEGIA
full or partial loss of sensation and movement in both legs and torso depending on location of lesion
caused by damage in thoracic T1-T12, Lumbar L1-L5 or Sacral S1-S5 areas
What are the layers of protection for the brain
Dura matter - outer most covering elastic layer surround brain
Arachnoid - under dura - not attached but close to brain sudural space in between
Pia matter - deepest layer, compromised of thin membrane that is close to the surface of the brain
(separated from arachnoid membrane via subarachnoid fluid space/cerebrospinal fluid)
What is the meninges
describes the 3 membranous layers that cover the brain and spinal cord
What is the function of meninges
- protection
- passage of cerebrospinal fluid - ventricular system
- support of cerebral and spinal blood vessels - vasculature system
What is the ventricular system
compromises a series of interconnected cerebrospinal fluid - filled spaces that lie at core of forebrain and brain stem
What is the ventricular system compromised of?
- lateral ventricles
- third ventricle
- fourth ventricle
What is the function of ventricular system
- protection
- transport
- regulation of buoyancy
What two pairs of arteries supply blood to the brain?
- ventrebal arteries
- internal carotid arteries
Vertebral arteries?
- converge near base of pons to form basilar artery
- basilar artery splits into right and left superior cerebellar arteries and posterior cerebral arteries at the level of midbrain
- posterior cerebral arteries send branches - posterior communicating arteries that connect to the internal carotid arteries
Internal carotid arteries?
- branch to form 3 middle cerebral arteries and the anterior cerebral arteries
- anterior cerebral arteries are connected by the anterior communicating artery
What is the vasculature system function?
- delivery of O2
- removal of CO2
- Transport
