• Describe and identify the major anatomical divisions of the CNS
• Describe the gross anatomy of the brain and spinal cord
Brain embryological regions:
1. Forebrain
- cerebrum - divided into 2 cerebral hemisphere separated by the longitudinal fissure,
connected by the corpus callous, responsible for continuous though processes and
intellectual function, memory storage, precessing and retrieval, conscious and
subconscious regulation of skeletal muscle contraction.
Structure: cortex = surface layer consisting of grey matter, thrown into folds: gyri
(elevations) separated by fissures = sulci. These arrangement increases the surface
area.
Subdivision: frontal, parietal, occipital, temporal lobes
Central sulcus = frontal/parietal
Lateral sulcus = frontal/temporal
Parietooccipital sulcus
Functional areas:
>primary motor area = anterior to central sulcus there is precentral gyrus which
controls voluntary movement
> Primary sensory area = post-central gyrus, receives and interprets sensations.
> Primary auditory area = inferior to lateral sulcus, on superior temporal gyrus,
reception and interpretation of sound
> motor speech (Broca’s) area = superior to lateral sulcus, on the left side of the brain
controls movements involved in speech
> Wernicke’s area = posterior section of the superior temporal gyrus on the left side of
the brain, comprehension of speech
> primary visual area = posterior pole of the occipital lobe around the calcimine
sulcus, receives visual impressions
- diencephalon = almost completely hidden from the surface, involved in bringing
sensory information to the cortex, autonomic control, consists of dorsal thalamus
(relay and processing center) and ventral hypothalamus (hormone production and
emotional control)
2. Midbrain
3. Hindbrain
- pons
- Medulla oblongata
- Cerebellum = co-ordination of complex somatic motor patterns, postural muscle =
maintains balance refined learned movement patterns.
(the brainstem) = involved in processing and relay centre for information passing to and
from cerebrum and cerebellum, contains reflex centers associated with respiratory and
cardiovascular functions. Consists of 3 parts:
- midbrain
- pons
- medulla oblongata
• Describe and identify the major arteries that supply blood to the brain, and
the cranial venous sinuses
The brain is supplied by:
- 2 internal carotid arteries (from common carotid arteries, arch of aorta) = leaves neck
by passing into cranial cavity through the carotid canal, passes upwards and
FORWARDS IN THE CAVERNOUS VENOUS SINUS (without communicating with it)
, then leaves sinus, passes lateral to the optic chiasma, terminates by dividing into
anterior and middle cerebral arteries.
- - 2 vertebral arteries (branch of subclaivian arteries) = ascend in the neck through the
foramina in the transverse processes of the upper six cervical vertebrae, enters cranial
cavity through foramen magnum, join together from either side to form the basilar
artery.
Four arteries anastomose on the inferior surface of the brain and form the circle of
Willis . Allows for collateral circulation of blood if one or part of the circle becomes
blocked or narrowed. Avoids ischemia
Auto-regulation of cerebral blood flow = needed to maintain a homeostasis, reduction in
cerebral blood flow stimulate release of vasoactive substances from the brain that cause
arterial dilation, cerebral smooth muscle in arterioles constricts in response to elevated
pressure.
Stroke = interruption of blood supply of the brain, 2 main causes: ischemic (blood clot)
and haemorrhagic (weakened blood vessels supplying the brain bursts)
ANterior cerebral = loss of blood supply effect primary motor cortex for lower limb and
perineum of contralateral side, can lead to incontinence due to lack of control of pelvic
floor muscles
Middle cerebral = blockage leads to loss of sensation and motor function of body except
lower limb, can effect the speech and the ability to understand the speech.
Posterior cerebral = supplies primary visual cortex = blockage leads to visual field
defects, supplies the hippocampus = leads yto loss of memory
• Describe and identify the three different meningeal coverings of the brain
1. dura mater = though, fibrous outermost covering
- cranial dura mata has a double layer: endosteal (periosteal) layer (covers the skull)
and meningeal layer (covers the brain, continuous through foramen magnum with
the dura mater of the spinal cord)
2. Archanoid mater = consists of archanoid membrane and the archanoid
trabecular which extends to the surface of the Pia mater
• Describe the gross anatomy of the brain and spinal cord
Brain embryological regions:
1. Forebrain
- cerebrum - divided into 2 cerebral hemisphere separated by the longitudinal fissure,
connected by the corpus callous, responsible for continuous though processes and
intellectual function, memory storage, precessing and retrieval, conscious and
subconscious regulation of skeletal muscle contraction.
Structure: cortex = surface layer consisting of grey matter, thrown into folds: gyri
(elevations) separated by fissures = sulci. These arrangement increases the surface
area.
Subdivision: frontal, parietal, occipital, temporal lobes
Central sulcus = frontal/parietal
Lateral sulcus = frontal/temporal
Parietooccipital sulcus
Functional areas:
>primary motor area = anterior to central sulcus there is precentral gyrus which
controls voluntary movement
> Primary sensory area = post-central gyrus, receives and interprets sensations.
> Primary auditory area = inferior to lateral sulcus, on superior temporal gyrus,
reception and interpretation of sound
> motor speech (Broca’s) area = superior to lateral sulcus, on the left side of the brain
controls movements involved in speech
> Wernicke’s area = posterior section of the superior temporal gyrus on the left side of
the brain, comprehension of speech
> primary visual area = posterior pole of the occipital lobe around the calcimine
sulcus, receives visual impressions
- diencephalon = almost completely hidden from the surface, involved in bringing
sensory information to the cortex, autonomic control, consists of dorsal thalamus
(relay and processing center) and ventral hypothalamus (hormone production and
emotional control)
2. Midbrain
3. Hindbrain
- pons
- Medulla oblongata
- Cerebellum = co-ordination of complex somatic motor patterns, postural muscle =
maintains balance refined learned movement patterns.
(the brainstem) = involved in processing and relay centre for information passing to and
from cerebrum and cerebellum, contains reflex centers associated with respiratory and
cardiovascular functions. Consists of 3 parts:
- midbrain
- pons
- medulla oblongata
• Describe and identify the major arteries that supply blood to the brain, and
the cranial venous sinuses
The brain is supplied by:
- 2 internal carotid arteries (from common carotid arteries, arch of aorta) = leaves neck
by passing into cranial cavity through the carotid canal, passes upwards and
FORWARDS IN THE CAVERNOUS VENOUS SINUS (without communicating with it)
, then leaves sinus, passes lateral to the optic chiasma, terminates by dividing into
anterior and middle cerebral arteries.
- - 2 vertebral arteries (branch of subclaivian arteries) = ascend in the neck through the
foramina in the transverse processes of the upper six cervical vertebrae, enters cranial
cavity through foramen magnum, join together from either side to form the basilar
artery.
Four arteries anastomose on the inferior surface of the brain and form the circle of
Willis . Allows for collateral circulation of blood if one or part of the circle becomes
blocked or narrowed. Avoids ischemia
Auto-regulation of cerebral blood flow = needed to maintain a homeostasis, reduction in
cerebral blood flow stimulate release of vasoactive substances from the brain that cause
arterial dilation, cerebral smooth muscle in arterioles constricts in response to elevated
pressure.
Stroke = interruption of blood supply of the brain, 2 main causes: ischemic (blood clot)
and haemorrhagic (weakened blood vessels supplying the brain bursts)
ANterior cerebral = loss of blood supply effect primary motor cortex for lower limb and
perineum of contralateral side, can lead to incontinence due to lack of control of pelvic
floor muscles
Middle cerebral = blockage leads to loss of sensation and motor function of body except
lower limb, can effect the speech and the ability to understand the speech.
Posterior cerebral = supplies primary visual cortex = blockage leads to visual field
defects, supplies the hippocampus = leads yto loss of memory
• Describe and identify the three different meningeal coverings of the brain
1. dura mater = though, fibrous outermost covering
- cranial dura mata has a double layer: endosteal (periosteal) layer (covers the skull)
and meningeal layer (covers the brain, continuous through foramen magnum with
the dura mater of the spinal cord)
2. Archanoid mater = consists of archanoid membrane and the archanoid
trabecular which extends to the surface of the Pia mater
