Nervous System Flashcards
What makes up the CNS
Brain + Spinal Cord
Functions of CNS
Integrates, processes, co-ordinates sensory data & motor commands
Function of PNS
Delivers Sensory information to CNS and carries out motor commands from CNS to peripheral tissue
What is a ganglion
Concentration of nerve cell bodies outside the CNS
Two divisions of PNS
Afferent and Efferent
Difference between afferent and efferent
Afferent = Sensory neurons, carries impulses towards brain Efferent = Motor neurons, away from brain
Two subsections of efferent division of PNS
Somatic and Autonomic
What does the somatic nervous system control
Skeletal muscle (voluntary contractions and reflexes
What does the autonomic nervous system control
Smooth muscle, cardiac muscle, diaphragm and glands (Involuntary AUTOmatic function)
Two subsections of the ANS
Sympathetic and Parasympathetic
Function Sympathetic division
Prepares body for flight or fight
Function of parasympathetic
Prepares body for rest & response
What are special senses
Located in special organs (vision, hearing, taste, smell, balance and acceleration)
Function of dendrites
Carry incoming impulses to cell body as graded potentials
What does the cell body of a nerve cell contain
Nucleus and Organelles
Function of an axon
Carries an action potential away from the cell body
What connects and axon the cell body and what may surround it
Axon hillock , myelin sheath
What are telodendria
Branching terminals of axon that synapse with another cell
What are unipolar neurons and what are most common type
Unipolar only have one attachment to cell body, most sensory neurons from skin are unipolar
What are bipolor neurons + examples
Have 1 processes from cell body: 1 axon and 1 fused dendrite. Found in retina, olfactory receptor cell
What are multipolar neurons and where are they found
Have many dendrites that attach to the cell body with a signal axon that ends in synpatic terminal, found in CNS, all motor neurons
List 4 types of neuroglia in CNS
Ependymal cells, astrocytes, microglia, oligodendrocytes
Function of astrocytes
control chemical environment around neurons
Function of microglia
Monitor neuron health are are macrophages
Function of oligodendrocytes
Produce myelin sheath and cholesterol
Two types of neuroglia in PNS
Satellite cells and Schwann Cells
Function of satellite cells
Surround cell bodies, supply nutrients and provide structure
Function of schwann cells
Form myelin sheath
What interrupts myelin sheath
nodes of Ranvier
Function of interneurons
Connect motor neurons to sensory neurons
What is resting membrane potential
Difference in distribution of ions between interior of a cell and extracellular fluid
What do all somatic motor neurons release at their synapses with skeletal muscle fibre
Acetylcholine
3 Meninges that surround the brain from outer to inner
Dura mater, arachnoid mater and pia mater
What is the dura mater
Tough outercoat of fibrous connective tissue
What is arachnoid mater
Attaches to inner surface of dura mater and ties arachnoid to pia mater (CSF fills the subarachnoid space and cushions brain agaist shock)
What is pia mater
Contacts the brain and contains many tiny blood vessels
Where does the cerbrum get 80% of it’s blood supply
R & L internal carotid arteries
What forms the basilar artery
R & L vertebral arteries
Function of circle of willis
Unites brain’s anterior and posterior blood supplies, connects basilar artery to the carotids, equalises blood pressure
Whats a CVA
Block to blood circulation in brain due to clot where brain tissue dies.
What is the blood-brain barrier
Endothelial cells of capillaries that serve brain are seamlessly joined together to each other by tight junction
Function of blood brain barrier
Seperates brain from flucations in hormones, amino acids and ions that occur in blood
What is the choroid plexus
Part of blood brain barrier but contains porous capillaries, plasma filtered through forms CSF
Function of cerebrospinal fluid
Cushions brain, transports dissolved gases, nutrients, wastes and chemical messengers
How does CSF re-enter blood
In supperior saggital sinus via arachnoid granulations
What does the cerebrum consist of
Gyri (ridges) and Sulci (Grooves) on the brain surface which are organised into lobes
What divides the left and right cerebral hemisphere
Longitudinal fissure
Central sulcus function
seperates frontal lobe from parietal lobe
Anatomyof each hemisphere
Has superifical layer of gray matter (cerebral cortex) over white matter .
What are the islands of gray matter inside white matter called
Basal nuclei
What is the cerebral cortex
our consicious mind
Function of diencephalon
Links the brainstem with surrounding cerebral hemispheres
What receptors does the hypothalamus have
Osmotic concentration, blood glucose and temp
Function of thalamus
Directs attention to stimuli of interest and elicits emotional response
Where is the pituitary gland
Dangles inferior to the hypothalamus by the infundibulum
What does the pineal gland produce and what is its function
Melatonin which regulates circadian rhythm and reproductive functions
What is circadian rhythm
physical, mental, and behavioral changes that follow a daily cycle
What makes up the brainstem
Midbrain, pons, medulla oblongata
Function of brainstem
Centres within produce programmed automatic behaviours necessary for survival
Function of cerebellum
Processes inputs from cerebral motor cortex, various brainstem nuclei and sensory receptors, subconsciously provides patterns of learned skeletal muscle contraction
What is the limbic system
Network of neurons that span large distance in the brain but work together
Functions of limbic system
Emotional brain
- makes us want to do tasks
- recorgnises facial expressions
- triggers emotional reaction to smells
- Produces emotion induced illness
- Allows emotion to override logic
Function of reticular formation
Receives and integrates all incoming sensory input
What is the spinal cord enclosed by
Single layer dura mater
What is a spinal cord break above L1 referred to as
Paraplegia
What is spinal cord break above C7 referred to as
Quadriplegia
What does spinal cord break above C5 cause
Possible respiratory failure or death
Where is the phrenic nerve located
Arises from spinal nerves C3, C4 and C5 and innervates the diaphragm
Where is the sciatic nerve located
L4, L5, S1-S3
What are spinal reflexes
Rapid predictable motor responses to a stimulus without processing by the brain
Reflex model pathway steps 1 - 5
1 Receptor
2 Sensory neuron transmits afferent impulses to CNS
3 Integration Centre in CNS
4 Motor neuron conducts efferent impulses to effector organ
5 Effector
Function of cranial reflexes
Check for damage to cranial nerves or associated processing centres in brain stem
Two neurons in ANS motor pathway
The preganglionic neuron and the unmyelinated post-ganglionic neuron
Function of preganglionic neuron
Runs from CNS to a ganglion
Function of unmyelinated post-ganglionic neuron
Runs from ganglion to effector
What do all parasympathetic neurons release
ACh
Parasympathetic effect on heart, lungs, eye, gut and reproductive system
Decreases HR, constricts bronchioles, constricts pupil, increases motility and secretions, sexual arousal
Sympathetic system effect on heart, lungs, eyes, gut, urinary, blood vessels, sweat glands, skeletal muscle, adipose tissue
Increases HR & strength of contractoin, dilates bronchioles increases resp rate and depth of breathing, dilates pupils, decreases motility and secretion, decreases blood flow to the kidneys, constriction or dilation, stimulates sweating, increases in glycolysis and muscle tone, lipolysis
4 regions of spinal cord
Cervical, thoracic, lumbar, sacral
What are anterior root branch
the axons of motor neurons
what are posterior root branch
the axons of sensory neurons
What are spinal ganglia
Contain cell bodies of sensory neuron that form the posterior root
What two things do all spinal nerves have
White ramus communicans and gray ramus communicans
Where does the posterior ramus supply to
skin/ muscles of back
Where does anterior ramus supply to
Most of body wall, skin, limbs
Describe form of gray matter
Butterfly/ H shape
What are nerve plexuses
Interwoven network of nerve fibres
Four major nerve plexuses
Cervical, brachial, lumbar, sacral
What are neural reflexes
Rapid, automatic response to specific stimuli
4 classifications of reflexes
development, motor response, complexity of neural circuit, site of information processing
What are innate reflexes
Basic neural reflexes formed before birth, are genetically programmed i.e withdrawal, chewing
What are acquired reflexes
Rapid, automatic learned motor patterns enhanced by repetition, i.e braking a car in emergency
