Lecture 8 Flashcards
Ganglion
Collection of cell bodies located in the PNS that have similar function
Nucleus
collection of cell bodies located in the CNS that have similar function
CNS
brain, spinal cord , cranium nerves
PNS
Motor ( efferent ) Sensory ( afferent )
Afferent
Approach the CNS
Efferent
Evades the CNS
Tract
bundle of CNS axons
Nerve
bundle of axons only in the PNS
Motor unit
lower motoneuron and its associated set of muscle fibres
Lower motoneuron
Cell body in the ventral horm of the spinal cord and axon that innervates skeletal muscle
Upper motoneuron
have their cell bodies in the
forebrain/brainstem and
send their axons to activate lower motoneurons
Somatic
of the body / part of the body / things you control
Visceral
deep organs, guts inner organs
Grey matter
Neuronal cell bodies
White matter
neuronal cell axons
Sensory function
Sensory function: receptors detect internal and external
stimuli, carrying this info to your brain.
Integrative function
NS processes sensory info by
analysing, storing and making decisions.
Motor function
Upon integration, the NS elicits an
appropriate motor response, activating effectors
(muscles/glands)
Neurons are the parenchymal cell
- Electrically excitable.
- Use action potentials (impulse).
- Stimulate/activate other neurons or target cells (muscle/gland).
Action potential
Resting membrane potential -70 mV
the synapse
Electrical vs Chemical Synapse
Neuroglia CNS - Astrocyte
Astrocyte :
anchor neurons and blood vessels
regulate the Extracellular environment
Repair damaged tissue
facilitate the formation of the blood-brain barrier
feed neurons
Blood-brain barrier
The wall between the brain and the blood cells ( facilitated by astrocytes )
Neurogilia CNS - Oligodendrocyte
Myelianate ( myelin sheath insulating ) specific axons in the CNS
makes signals faster
ie stubbing toe at night takes a while to feel pain
Neuroglia CNS - microglial cell
Acts as phagocytes
fun fact brain doesn’t have white blood cells so the microglial cells
Neuroglia CNS - Ependymal cell
- line cavities
- cilia circulate fluid around brain and spinal cord
some secrete this fluid
Schwann and satellite cells
The skin of the brain
- zero connective tissues in the brain
- ## Meninges are like the skin of the brain
Dura mater
outer part and folds of the dura mater help stabilise the position of the brain
Dural folds produce venous sinuses to drain blood from the brain
thick leather type
Arachnoid mater
looks like a spiderweb in microscope
Holds in CSF
Pia mater
a contains nerves & blood vessels to nourish cells
Gyri
brain is folded prod
Sulci
Folding
Fun fact : Everyones brain does not look the same
there is weak association between folds in the brain and smartness
CNS has 4 main parts
Cerebrum has 5 lobes and 4 are related to the skull bones
5th lobe limibic lobe
6th lobe insula
Hemispheric specialisation
Cerebellum
Cerebellum –interactions between regions
together coordinate movement
* Ridges (folia) cover exterior cerebellar surface; separated by shallow sulci; increases surface area of region
Brainstem
one of the oldest components of the brain; vital to
immediate survival
* Nuclei control/function in – Basic homeostatic functions (heart rate and breathing rhythms)
– Reflexes (programmed, automatic responses to stimuli) – Movement, sensation, and maintaining alertness
Ventricles
like a system of caves in the brain
Laterals connect to the third ventricle and then run to the mesencephalic aqueduct and then go into the fourth ventricle
CSF constantly flows through these ventricles starting from the lateral ventricles
CSF circulation
CSF starts producing from birth
CSF is made by the choroid plexus
Flows around the brain and spinal cord and is reabsorbed into venous circulation via arachnoid villi that pierce the dura
Blockage produces hydrocephalus
around 500 mls of CSF per day
Thalamus
gateway to the cortex from the rest of the nervous system
It lies either side of the third ventricleIt receives input from all areas of the nervous system
Hypothalamus
Controls the ANS function
This region controls
hunger, thirst, sexual
feelings, hormone
and temperature
regulation (basically, it
regulates body
homeostasis)
Basal Ganglia
collection of 5 nuclei involved in the initiation of movements
Corpus callosum
Brain hemispheres are connected by a bridge of axons called the corpus callosum
Some people are actually born without one and recently some people used to have it cut out who had dangerous seizures
people who have no corpus callosum may act like they have independent control of their two sides of the brain
