Neuroanatomy I: The Cerebral Cortex: Gross and Functional Anatomy Flashcards

(51 cards)

1
Q

Three embryological regions of the brain

A

Forebrain [Cerebrum | Diencephalon]

Midbrain

Hindbrain [Pons | Medulla oblongata | Cerebellum]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Cerebrum (cerebral hemispheres)

A
  • Largest area of brain
  • Divided into two cerebral hemispheres
  • Separated by the longitudinal fissure
  • Connected by the corpus callosum
  • Conscious thought processes & intellectual function
  • Memory storage, processing & retrieval
  • Conscious & subconscious regulation of skeletal muscle contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Cortex

A
  • Surface layer
  • Gray matter

Increases surface area:

  • Thrown into folds - Gyri
  • Separated by fissures - Sulci
  • Subdivide surface into lobes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Lobes of the Cerebral Hemispheres

A
  • Frontal lobe
  • Parietal lobe
  • Temporal lobe
  • Occipital lobe
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Lobes & Sulcus of the Cerebral Hemispheres

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Precentral Gyrus

A

(anterior to central sulcus)

  • Primary motor area
  • Controls voluntary movement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Post-central gyrus

A

(posterior to central sulcus)

  • Primary sensory area
  • Receives & interprets sensations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Superior temporal gyrus

A
  • Primary auditory area
  • Reception and interpretation of sound
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Motor speech (Broca’s) area

A
  • Located just above lateral sulcus, usually on the left side of the brain
  • Controls movements involved in speech
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Wernicke’s area

A
  • Located in the posterior section of the superior temporal gyrus on the left side of the brain
  • Comprehension of speech
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Calcarine sulcus & Primary visual area

A
  • Located on the posterior pole of the occipital lobe around the calcarine sulcus
  • Receives visual impressions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Cerebellum (cerebellar hemispheres)

A
  • Co-ordinates complex somatic motor patterns
  • Postural muscles-maintains balance
  • Refines learned movement patterns
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The Brainstem

A

[Medulla oblongata | Pons | Midbrain]

  • Processing and relay centre for information passing to and from cerebrum & cerebellum
  • Contains reflex centres associated with respiratory & cardiovascular functions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Diencephalon

A
  • Region of the brain almost completely hidden from the surface
  • Consists of dorsal thalamus & ventral hypothalamus

Diagram (back of skull)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The diencephalon consists of the following structures:

A

Thalamus: Relay & processing centre

Hypothalamus: Involved in hormone production & emotional control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The brain is supplied by…

[Arterial Supply of the Brain]

A

Two internal carotid arteries

Two vertebral arteries (a branch of subclavian artery

Four arteries anastomose on the inferior surface of the brain & form the circle of Willis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Internal Carotid Arteries

A
  • Leaves neck by passing into cranial cavity through the carotid canal
  • Passes upwards & forwards in the cavernous venous sinus (without communicating with it)
  • Then leaves sinus, passes lateral to the optic chiasma
  • Terminates by dividing into anterior & middle cerebral arteries
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Vertebral Arteries

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Circle of Willis

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Function of the Circle of Willis

A

Allows for collateral circulation of blood if one or part of the circle becomes blocked or narrowed

Avoids ischemia

The left middle & anterior cerebral arteries are filled via the contralateral anterior & posterior communicating branches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Autoregulation of Cerebral Blood flow

A

The ability of the brain to maintain relatively constant blood flow

Due to the need for a constant blood supply & water homeostasis

§ Reductions in cerebral blood flow stimulate release of vasoactive substances from the brain that cause arterial dilatation

§ Cerebral smooth muscle in arterioles constricts in response to elevated pressure

22
Q

Stroke

A

Interruption of blood supply to parts of the brain

Causes (two main):

Ischaemic - blood supply is blocked due to a blood clot (85% of all cases)

Haemorrhagic - where a weakened blood vessel supplying the brain bursts

23
Q

Blood Supply in Brain Function

(Cerebral Vascular territories)

A
  • Anterior cerebral
  • Middle cerebral
  • Posterior cerebral
24
Q

Anterior Cerebral

A

Loss of blood supply effect primary motor cortex for lower limb & perineum of contralateral side

Can lead to incontinence (unintentional passing of urine) due to lack of control of pelvic floor muscles

25
Middle Cerebral
* Blockage will lead to loss of sensation & motor function of body except for lower limb & perineum * Also supplies Broca’s motor speech area & Wernickes sensory speech area * Loss of function can effect how someone speaks & the ability to understand speech
26
Posterior Cerebral
• Supplies **primary visual cortex** § Blockage can lead to visual field defects • Supplies the **hippocampus** § Blockage can lead to memory loss
27
The Meninges
_Three_ protective membranes **Dura mater** § Tough, fibrous outermost covering **Arachnoid mater** § Consists of arachnoid membrane & the arachnoid trabeculae which extends to the surface of the Pia Mater **Pia mater** § Blood vessels run along the surface of the pia mater within subarachnoid space
28
Cranial Dura Mater
_Conventionally described as a double layer:_ - **Endosteal (or periosteal) layer** - (actually periosteum covering the skull) - **Meningeal layer (Dura mater proper)** § Covers the brain § Continuous through foramen magnum with the dura mater of the spinal cord
29
Cranial Dura Mater – Meningeal Layer
Sends inward four septa that divide the cranial cavity into freely communicating spaces, lodging the subdivisions of the brain ## Footnote Function of the septa: • Restrict rotatory displacement of the brain
30
Reflections of Dura Mater
Falx cerebri Diaphragma sellae Falx cerebelli Tentorium cerebelli Tentorial notch
31
Venous Sinuses
**- Situated between periosteal & meningeal layers of dura mater** Receive tributaries (a vein that empties into a larger vein) from the brain, skull bones, the orbit & the internal ear
32
Extradural (between periostreal dura mater & the meningeal dura mater – dura mater proper) **[Intracranial Haemorrhages]**
**May result from trauma or cerebral vascular lesions (raises intracranial pressure)**
33
Subdural (between dura & arachnoid mater) **[Intracranial Haemorrhages]**
**Due to mainly head trauma (displacement to skull - realtively slow build up of intracranial pressure)** Tearing of veins as they enter superior sagittal sinus Blood accumulates in potential space between dura & arachnoid mater
34
Subarachnoid (between the arachnoid mater externally and pia mater internally) **[Intracranial Haemorrhages]**
* Leakage or rupture of circle of Willis * Severe headache | loss of consciousness Diagnosed by withdrawing heavily blood-stained cerebrospinal fluid through a lumbar puncture
35
Ventricular System & Central Canal
Ventricular System: CSF filled central passageway - (Passageway -\> Ventricles) * Extends along spinal cord (Central Canal) & brain * Filled with cerebrospinal fluid (CSF) - Continuously circulated fluid which also surrounds the brain & spinal cord - Provides a protective cushion - Transports nutrients & waste
36
Ventricular System of the Brain
37
Cerebrospinal Fluid (CSF)
* Clear, colourless fluid formed by the choroid plexus (coloured red) * Circulates through the ventricular system * Enters the subarachnoid space through three foramina in the roof of the fourth ventricle * Circulates both upwards over the surface of the cerebral hemispheres & downwards over the spinal cord * Eventually enters bloodstream by passing through arachnoid villi into the dural venous sinuses, in particular the superior sagittal sinus
38
Cerebrospinal Fluid (CSF) function
* Removes waste products of neuronal activity * Fluid cushion for protection
39
40
Hydrocephalus
**Overproduction of CSF or blockage of the ventricular system leading to accumulation of CSF** ## Footnote § In a neonatal skull the increase in pressure will force unfused cranial bones apart leading to cranial abnormalities as well as neurological complications § In a fused adult skull leads to a dangerous rise in intracranial pressure
41
How can Hydrocephalus be treated?
A shunt that drains the CSF from the ventricular system into a body cavity where it can be reabsorbed
42
Ventral Surface of the Brain
43
Cranial Nerves
44
Cranial Nerve Table Way to Remember Cranial Nerves: **_O_**n **_O_**ccasion **_O_**ur **_T_**rusty **_T_**ruck **_A_**cts **_F_**unny **_V_**ery **_G_**ood **_V_**ehicle **_A_**ny **_H_**ow
_Sensory | Motor | Both:_ **_S_**ome **_S_**ay **_M_**arry **_M_**oney **_B_**ut **_M_**y **_B_**rother **_S_**ays **_B_**ig **_B_**rains **_M_**atter **_M_**ore
45
Olfactory Nerve
Cribriform Plate with foramina It supports the olfactory bulb, and is perforated by olfactory foramina for the passage of the olfactory nerves to the roof of the nasal cavity to convey smell to the brain
46
Olfactory Nerve
47
Optic Nerve
II - Optic - Sensory - Vision
48
Optic Nerve
49
Vagus Nerve
X - Vagus - Mixed - Taste | sensory to thoracic & abdominal viscera; Movement & secretion The vagus nerve travels through the middle portion of the jugular foramen
50
Vagus Nerve Features
* Longest cranial nerve in the body * Innervates the skin of the external acoustic meatus & the internal surfaces of the laryngopharynx & larynx * Provides visceral sensation to the heart & abdominal viscera * Provides taste sensation to the epiglottis & root of the tongue * Provides motor innervation to the majority of the muscles of the pharynx, soft palate & larynx. * Parasympathetic innervation the smooth muscle of the trachea, bronchi and gastro-intestinal tract & regulates heart rhythm
51
What is the longest cranial nerve in the body?
Vagus Nerve