Anatomy and Physiology Flashcards
(212 cards)
What are the cerebral hemispheres divided by?
sulci form lobes which are part of the hemispheres formed by gyri
What are:
Sulci?
Gyri?
Groove on brain
Ridge-like elevation
List the lobes of the brain.
- Frontal
- Parietal
- Occipital
- Temporal
- Limbic
- Insula
List the regions of the CNS (4). Give specific parts of each region.
- Spinal cord
- Brainstem (nuclei of all CN bar CN I + CN II)
a) Medulla
b) Pons
c) Midbrain - Cerebellum
4. Cerebrum
a) Telencephalon (cerebral hemispheres)
b) Diencephalon (thalamus + hypothalamus)
What are the two main appearances of the CNS?
Where are they located in:
i) The Brain
ii) The Spinal Cord
1) Grey Matter: Cell bodies of neurones + neuroglia + unmyelinated neurones
• Nucleus (CNS)
• Ganglion (PNS)
• Surface of cerebral and cerebella hemispheres
Locations:
• Brain: Grey matter outside
• Spinal cord: Grey matter in centre
2) White Matter: Axons of myelinated neurones.
Locations:
• Brain: White matter is central
• Spinal cord: White matter is peripheral
What are meninges?
List the meningeal layers.
Membranes which protect the encephalon and spinal cord in addition to bones and vertebra and cerebrospinal fluid
1) Dura mater: superficial and toughest meninges layer which has two layers: outer periosteal layer and inner meningeal layer. Apart from the dural sinuses, these two layers are in apposition.
2) Arachnoid mater: Middle layer, adhered closely to the dura with a web-like appearance
3) Pia mater: Deepest layer which is in direct contact with CNS tissue (encephalon + spinal cord) which is highly vascular and enters every sulci
What is the term for the inward layer of dura delving to divide the brain into two hemispheres?
What does this allow functionally?
Falx cerebra: Inward septa of dura (Dural partitions)
Brain secured to skull (periosteum connected to outer meninges)
Which is the innermost layer of the meninges, in direct contact with CNS tissue?
Pia mater
What is a meningeal space?
List the 3 meningeal spaces.
Spaces between meningeal layers
1) Epidural space: Potential space of Dura mater to Bone
2) Subdural space: Potential space of Dura to Arachnoid
3) Subarachnoid space: Real space containing CSF + Cerebral arteries between Arachnoid and Pia mater
What is the term for the two external invaginations and evaginations of the cerebrum?
1) Gyri (gyrus): Rises
2) Sulci (sulcus): In-folding
Give the term of the sulcus separating the brain into two cerebral hemispheres.
Median longitudinal fissure is a sulcus separating the two cerebral hemispheres
List three identifiable regions of Dural septa.
Tentorium cerebelli
Tentorial notch
Falx cerebelli
Outline the two divisions of the ANS.
Give:
- Outflow
- Pre-ganglionic NT
- Post-ganglionic NT
- Effects
1) Sympathetic
• Thoracolumbar
• Pre-ganglionic sympathetic neurons: T1-L2 spinal cord (thoracolumbar)
• Ganglia in sympathetic chain
• Pre-ganglionic NT: ACh @ Nicotinic
• Post-ganglionic NT: NE @ Adrenergic (NB: Sweat gland is ACh and Adrenal Medulla)
• Effects: Mydriasis, tachycardia, vasoconstriction, tachypnea, bronchodilation, glycogenic, diaphoresis
2) Parasympathetic
• Craniosacral
• Pre-ganglionic parasympathetic neurons: brainstem + S2-S4
• Pre-ganglionic NT: ACh @ Nicotinic
• Post-ganglionic NT: ACh @ Muscarinic (PAM)
• Effects: Meiosis, GI motility (peristalsis), glandular secretion, excretion (defaecation) and micturition
Outline the embryological development of the nervous system (spinal cord).
• Ectoderm -> Neural plate -> Neural tube closes -> Neural crest cells give rise to NS cells: Melanocytes, Schwann Cells, Adrenal medullary cells, dorsal root ganglion cells, autonomic ganglion cell
What germ layer is the neural tissue derived from?
Ectoderm
List 3 types of glial cells and their functions.
• Oligodendrocytes: myelination formed by these cells which is a spiral multi-layered wrapping of glial membrane increasing AP conduction speed by restriction of ionic current to smaller unmyelinated portions at nodes of Ranvier
- 1 oligodendrocyte to many myelinated CNS axons
• Microglial cells: Immune responses within CNS removing cellular products by phagocytosis assisted by other glia and phagocytes invading CNS from circulation
• Astrocytes: named by morphology with cell body and several branches arising which produces BBB, regulates the CNS microenvironment by buffering EC environment with ions and NTs, local astroglia take up excess K+, post-injury astrocytes ∆ to become reactive astrocytes forming glial scar (segregating damaged tissue) and couples GAP junctions to form sanctum for small molecules and ions to redistribute along concentration gradients or by current glow.
• Ependymal cells: epithelium lining ventricular spaces of the brain which secretes CSF in ventricular system where the substance diffuses readily across ependymal lining between EC space of brain and CSF
• Satellite cells: encapsulate dorsal root and cranial nerve ganglion cells regulating microenvironment like astrocytes
List 3 features of a neurone.
1) Dendrites: branching extensions of soma which expands SA of neurone to receive signals from other neurones which can be primary or higher-order. Individual dendrites aggregate into dendritic trees ≈ ∆ between different neurone types, size, number and spatial organisation
2) Soma (cell body): core of neurone bearing genetic and metabolic centres of neurones” nucleus, nucleolus, Nissl bodies (neuronal biosynthetic apparatus ≈ RER + Golgi Body), mitochondria, cytoskeletal elements). Soma receives synaptic input from dendrites
3) Axon: extension of cell body, as proximal dendrite in specialised region called axon hillock, conveying output of cell to other neurones with variable length and diameter ∆s according to neuronal type. Axon is absent of RER, free ribosomes and Golgi apparatus. Axon may terminate in a synapse and may make synapses along its length.
List 3 types of neurone based on polarity.
- Multipolar neurone: Most abundant in CNS where dendrites branch directly of soma and single axon arises from axon hillock
- Pseudounipolar neurone: Spinal ganglion with dendritic axon receiving sensory information from periphery sending to spinal cord via an axon bypassing cell body along the way ≈ relay sensory information from peripheral receptor to CNS w/o modifying signal
- Bipolar neurone: retina and olfactory epithelium with main dendrite receiving synaptic input conveyed to cell body and from there through axon to next layer of cells. Bipolar neurones integrate multiple inputs and then bypasses modified information to next neurone in the chain. Difference between pseudounipolar and bipolar neurone ≈ amount of processing occurring in neurone
What is radial migration?
- Cells migrate along radial glia from origin in ventricular and subventricular zones –> formation of cortex and deep nuclear structures
- Radial migration gives rise to projection neurons of the cortex
List the 4 lobes of the brain and their main functions.
1) Frontal lobe: Motor functions and Personality and ability to change; ‘frontal lobe personalities’
2) Temporal lobes: Memory and speech (L > R)
3) Parietal lobe: Spatial awareness ( R ), Language (L)
4) Occipital lobes: Vision
Which lobe of the brain is primarily responsible for motor functions and personality?
Give one way you can test this.
Frontal lobe: Motor functions and Personality and ability to change; ‘frontal lobe personalities’
• Sequencing and fluency
Which lobe of the brain is primarily responsible for memory and speech?
Which hemisphere are these features more dominant in for a Right Handed person?
How would you test this?
Temporal lobes: Memory and speech (L > R)
L > R
Test(s):
• Address test: Give a pseudo address and see if they remember it
• Object recall
• Serial 7s
Which lobe of the brain is primarily responsible for spatial awareness and language?
Which hemisphere are these features more dominant in for a Right Handed person?
How would you test this?
Parietal lobe: Spatial awareness ( R ), Language (L)
Right side is awareness
Left side is Language
Tests: • Clock face: Put numbers on and draw ten to two, neglecting one side of space, put all on one side • Naming objects • Drawing cube, interlocking infinity • Agnosia
Which lobe of the brain is primarily responsible for vision.
Occipital lobes: Vision