brain development and anatomy and division of cellular type and labour in organisms: vasculature Flashcards
what parts of anatomy are part of neuroanatomy?
- spinal cord
- brain stem
- cerebellum
- diencephalon
- cerebral cortex
what is the anatomy of the neuron?
- cell body
- dendrite
- axon
- synapse
- (spine)
what does the ectoderm give rise to?
the neural plate
what is the neural plate?
its the precursor of the central and peripheral nervous systems
how does the nervous system form during development?
first it forms the neural plate, then the neural groove then the neural tube
what are the underlying molecular mechanisms for the development of the nervous system?
BMP signalling
what is neural induction?
its the folding proccess in vertebrate embryos, which includes the transformation from neural plate to neural tube
how does the neural ectoderm form?
it forms when BPM signalling pathways are suppressed
what are the different types of patterning in the nervous system?
- rostocaudal patterning
- dorsoventral patterning
- forebrain patterning
what is dorsalventral patterning?
- the ventral neural tube is patterned by sonoc hedgehog protein which is secreted by the notochord and floor plate
- the dorsal neural tube is patterned by bone morphogenetic proteins
what molecules are involved in forebrain patterning and what do they do?
FGF8- establishes the rostocaudal pattern of the cerebral cortex
Pax6 and Emx2- mutually repress each others’ expression
what is the ‘cortex’?
- its the ‘higher’ part of the brain involved in complex cognitive processes and ‘thinking’ and ‘planning’ and ‘remembering’
- its highly folded in humans to give it more surface area
what happens during brain development in the embryo?
- during brain development, new neurons migrate along radial glia from the ventricles to form the cortex layers
- ## this movement is called ‘inside-out’: inner layers of cells are created first, then outer layers of cells
what causes morphological changes in the brain during lissencealphy?
- anything ehich inhibits the migration of neurons along the glia from the ventricles to form the cortex layers
what is a ‘neurodevelopment disaster’?
its mutations affecting the function of microtubules alter the ability of cells to move from, and migrate to their correct destination during the formation of the brain
what is lissencealphy?
its a smooth brain caused by mutations in the neurodevelopmental pathway
what other neurodevelopment problems are there?
- microcephaly
- autism
- psychiatric disorders such as schizophrenia
what brain dosorders are caused by a loss of neurons (neurological diseases)?
- alzheimers disease
- parkinsons disease
- stroke
what brain disorders are based on changes in neural circuit (neuropsychiatric diseases)?
- schizophrenia
- depression
- addiction
- autism spectrum disorder
what are the main factors that influence blood pressure?
- cardiac output (CO)
- peripheral resistance (PR)
- blood volume
how do you work out blood pressure?
=CO x PR
what does maintainingblood pressure require?
- cooperation of the heart, blood vessles and kidneys
- supervision of the brain
what is cardiac output determined by?
- venous return and neural and hormonal controls
what is resting heart rate controlled by?
- the cardioinhibitory centre via the vagus nerves
- stroke volume is controlled by venous return
- under stress, the cardio-acceloratory centre increases the heart rate and stroke volume
what are the properties of muscualr arteries and arterioles?
muscualr arteries- distal to elastic arteries, they deliver blood to body organs, they have thick tunica media with more smooth muscle and less elastic tissue
arterioles - they’re the smallest arteries which lead to capillary beds, they control flow into capillary beds via vascodilation and constriction
what are the properties of elastic arteries?
theyre thick-walled arteries near the heart; the aorta and its major branches
- large lumens allow low-resistance conduction of blood
- they contain elastin in all three tunics
- withstand and smooth out large blood pressure fluctuations
- allow blood to flow fairly continuously through the body
what are the properties of capillaries?
their primary function is to permit the exchange of nutrients and gases between the blood and tissue cells
- capillaries are the smallest blood vessels
- the walls consist of a thin tunica internal, one cell thick
- they allow only a single red blood cell to pass at a time
- pericytes on the outer surface stabilise their walls
- the three structural types of capillaries are: continuous, fenestrated and sinusoids
what are the properties of veins?
- theyre formed when venules converge
- they’re made of three tunics, with a thin tunica media and a think tunica external made up of collagen fibres and elastic networks
- capacitance vessels (blood resivoirs) that contain 65% of the blood
what is pressure (P)?
- the heart generates P to overcome resistance
- absolute pressure is less important than pressure gradient
- the pressure gradient is circulatory pressure (delta P)
what is delta P?
its the difference between pressure at the heart and pressure at the peripheral capillary beds
what is intrinsic control?
contraction: control of local blood flow, vascular smooth muscle intrinsic myogenic tone, stimulates smooth muscle one in response to pressure
vascodilation: vascular endothelium, relaxes smooth muscle
