Week 2 - Anatomy and Physiology of the Central Nervous System Theory - Part 2 Flashcards
(56 cards)
1
Q
What is the cerebral cortex
A
the outermost layer of the brain, made of folded gray matter. It is divided into 2 hemispheres and contains the 4 brain lobes
2
Q
How many hemispheres are there in the brain
A
2
3
Q
How many brain lobes are there
A
4
4
Q
Why is the brain highly folded
A
increases the brain’s surface area and allows for more neurons to be packed into the limited space of the skull.
5
Q
What is sulci (singular sulcus)
A
grooves of furrows in the brain’s surface
6
Q
What are gyri (singular gyrus)
A
raised ridges of brain tissue between the sulci
7
Q
What are the 4 lobes of the brain
A
- Frontal
- Parietal
- Occipital
- Temporal
*Note: Limbic system on medial surface
8
Q
What are the 3 key functional areas of the cerebral cortex
A
- Motor
- Sensory - conscious perception
- Association
9
Q
What are the motor functional area of the cerebral cortex
A
- Primary motor cortex (pre-central gyrus) - allows precise skilled voluntary movements
- Premotor cortex just anterior to primary motor cortex - learned/ repetitive movements
RED
10
Q
What is the sensory functional area of the cerebral cortex
A
- Postcentral gyrus for primary somatosensory
- Also visual, auditor, gustatory and olfactory cortex
BLUE
11
Q
What is the association functional area of the cortex
A
- integrates and interprets information
- responsible for higher level processing such as thinking, memory, reasoning and language
- Contribute to cognition - cortical areas outside of primary motor and sensory cortices
- largely receive highly processed sensory information
e.g. 1: association areas in posterior cortex (parietal temporal and occipital) related a perception of body image
e.g. 2: prefrontal association cortex involved in abstract thought as well as contribute to the planning of actions and movement
12
Q
What is the diencephalon
A
small but vital part of the brain located deep between the cerebrum and the brainstem. It acts as a relay center and regulates key functions like sensory processing, hormone control and autonomic regulation
13
Q
What are the main structures of the Diencephalon
A
- Thalamus
- Hypothalamus
- Epithalamus
14
Q
What is the thalamus
A
- key gateway nucleus
- primarily involved in somatic (sensory) function
- relays sensory signals (except smell) to the cerebral cortex
- Almost all sensory and some motor pathways have inputs into this nucleus
15
Q
What is the hypothalamus
A
- involved in visceral (e.g. thermoregulation), autonomic and endocrine functions
- controls homeostasis (body temperature, hunger, thirst, sleep)
- Forms a core part of the limbic system
- forms part of the emotional response (pleasure, fear ect)
16
Q
What is the epithalamus (includes pineal gland)
A
- pineal gland secretes melatonin
- regulates sleep wake cycle
- connects the limbic system to the brain
17
Q
Where is the cerebellum
A
back of the brain beneath the occipital lobe
18
Q
What is the function of the cerebellum
A
- Has a prominent role in motor control
- receives collateral inputs from upper motor neurons and spinocerebellar sensory inputs and thus is able to compare the 2
- Involved in some reflexes
- play an integrative role in cognition, speech, attention and emotional regulation
- helps modify behaviour in context of the environ - facilitated through cerebrocerebellar connections with prefrontal, parietal and temporal cortices
19
Q
What does the hindbrain include
A
- pons
- medulla oblongata
20
Q
What is the function of the hindbrain
A
- located at the back of the brain beneath the cerebrum and above the spinal cord
- pons sit above the medulla and connects the cerebellum tot he rest of the brain
- controls cardiovascular and respiration
21
Q
What are meninges
A
3 protective membranes that surround and cover the brain and spinal cord. Their main function is to protect the central nervous system, cushion the brain and support blood vessels.
Also contains cerebrospinal fluid (CSF) which helps to protect the brain from shocks.
22
Q
How many meninges layers are there
A
3
23
Q
What are the 3 layers of the meninges
A
- Dura mater (outer layer)
- Arachnoid Mater (middle layer)
- Pia Mater (inner layer)
24
Q
What is the dura mater
A
- tough (lots of collagen) - thickets and strongest membrane
- contains blood vessels and nerves
- has 2 layers
- contains large venous sinuses
sensory innervation: predominantly trigeminal to all 3 cranial fossae with the posterior fossa having afferents from C1-C3
25
What are the 2 layers of the dura mater
Periosteal layer - attached to the inner surface of the skull
Meningeal layer - closer to the brain including falx cerebri and tentorium cerebelli
26
What is the arachnoid mater
- composed of a barrier layer and spindly cells that cross the subarachnoid space
- subarachnoid space contains cerebrospinal fluid (CSF)
27
What is the pie mater
- very thin layer
- follows contours of cortex down into sulci
28
What is the flax cerebri
crescent shaped Dural fold that separates the 2 cerebral hemispheres of the brain
- made of dura mater
- extends vertically down the midline between the the left and right cerebral hemispheres
29
what is the tentorium cerebelli
crescent shaped dural fold that separates the cerebrum(occipital lobes) from the cerebellum
- part of the dura mater
- horizontal
30
What are dural sinuses
- *are venous channels*
- *located within the dura mater (outer layer of the meninges)*
- *primary function is to collect venous blood from the brain and return it to the jugular veins to be transported to the heart*
31
What are the 3 main dural sinuses
- superior sagittal sinus
- inferior sagittal sinus
- straight sinus
32
What are ventricles of the brain
The ventricles of the brain are hollow, fluid filled cavities located within the brain that are responsible for producing and circulating cerebrospinal fluid (CSF)
33
What are the types of brain ventricles
- lateral ventricles
- third ventricle
- fourth ventricle
34
What is the lateral ventricles
- there are 2 lateral ventricles one in each hemisphere of the brain
- they run within the main cerebral lobes
35
Where is the third ventricle
lies within the diencephalon
36
Where is the fourth ventricle
lies within the brain stem with the cerebral aqueduct within the midbrain
37
What is cerebrospinal fluid (CSF)
the interstitial (intercellular) fluid
- clear colour-less fluid that surrounds the CNS and runs in the ventricles and central canal of the spinal cord
- Mostly comprised of water and some salts and very low protein concentration
- made by ependymal cells in the choroid plexus
38
How much cerebrospinal fluid does a human have
125-150 mls
39
What are the 4 functions of the cerebrospinal fluid
- Buoyancy - brain floating
- Protection - shock absorber
- Homeostasis - allows equilibration of substances
- Perfusion - decrease intracranial pressure, increase blood waste clearance
40
What are arachnoid granulations
small, finger like projections of the arachnoid mater (middle layer of the meninges) into the dural sinuses.
Primary function is to allow the **reabsorption of cerebrospinal fluid (CSF)** from the subarachnoid space into the venous bloodstream
41
What arteries supply the arterial supply to the head and neck
carotid arteries
vertebral arteries
42
What is the circle of willies
*circular network of arteries located at the base of the brain that provides collateral circulation to the brain. It helps to ensure continuous blood flow to the brain even if one part of the arterial system becomes blocked or narrowed*
BELOW IS INFERIOR VIEW
43
What are the 3 main arteries serving the brain
- Anterior cerebral artery (ACA)
- Middle cerebral artery (MCA)
- Posterior cerebral artery (PCA)
44
What does the anterior cerebral artery (ACA) supply
- supplies medial cortex to the parietooccipital sulcus
- Also a small branch that contribute to blood supply of the internal capsule
45
What does the middle cerebral artery (MCA) supply
- main continuation of internal carotid receiving as much as 80% of blood from ICA
- Supplies large parts of the lateral surface of the brain as well as internal capsule, thalamus and striatum
46
What does the posterior cerebral artery (PCA) supply
branches to midbrain, occipital cortex and temporal cortex as well as thalamus
47
What supplies blood to the hindbrain
- Supplied by branches from basilar and vertebral arteries
*
Although many strokes affect the cerebrum, probably most common other area is that covered by PICA-lateral medulla and cerebellum - resulting in vertigo, fall towards side of lesion, nausea and truncal ataxia
48
What are venous sinuses
The venous sinuses of the brain are specialized channels that collect deoxygenated blood and cerebrospinal fluid (CSF) from the brain and return it to the venous circulation (via the internal jugular veins).
49
How are venous sinuses drained
Superficial veins in subarachnoid space -> drain into venous sinuses -> then to internal jugular
50
How is blood flow regulated
- Controlled by autoregulation and blood vessels respond to a range of metabolic factors (CO2, O2 levels and pH) to match the metabolic needs of the particular brain area
- Also regulated by arteriole intraluminal pressure - myogenic response - related to blood pressure
- CO2 response mediated by changes in H+ concentration
- Rise in CO2 leads to vasodilation - potential to faint on hyperventilation
51
What is the brain blood barrier
protective barrier formed by tightly packed cells lining the blood vessels in the brain. These restrict the movement of substance from the blood stream into the brain.
- it includes astrocytes that help regulate what passes through
function
- protect the brain
- regulate passage of nutrients, ions and neurotransmitters into the brain
- prevents neurotoxicity - blocks many drugs ad chemicals that could disrupt brain function
- selective permeability - allows essential substances like O2, glucose and amino acids to pass while keeping harmful molecules out
52
What is the limbic system
group of interconnected brain structures involved in emotion, memory, motivation, and behavior. It plays a key role in regulating emotional responses, forming memories, and controlling basic survival instincts like hunger and fear.
53
Where do the upper motor neurons decussate in the corticospinal tract
Medulla Oblangata
54
Where do the lateral ventricle run within
the main cerebral lobes
55
Where do the third ventricles lie
diencephalon
56
Where does the fourth ventricle lie
within the brainstem with the cerebral aqueduct within the midbrain
