GUMES nervous tissue Flashcards
what are the two types of cell found in the nervous system
neurons and glial cells
what are neurons
nerve cells
what are glial cells
supportive cells in the nervous system that do not function to conduct electrical impulses
what is the most abundant cell type in the nervous system
glial cells
what does the somatic nervous system divide into
somatic afferent and motor efferent
what are dendrites
where synapses occur, contain nissl bodies and usual organelles
receive electrical impulses which are processedin the cell body
what is the cell body of neurons
contains nucleus and nissl bodies but does not have centrioles as they do not divide
what are nissl bodies
clusters of free ribosomes and rough endoplasmic reticulum
what do axons do
conduct the electrical signal toward the axon terminal
what is a nerve
a complex that can have many axons
how many axons can a neuron have
one
what is the function of astrocytes
- form the blood brain barrier
- scar tissue formation after brain injury
- provide nutrients to neurons
- maintain the chemical environment and take up excess neurotransmitter
what is the function of microglia
defence role as they are the macrophages of the cns
clear debris from dead cells
what is the function of ependymal cells
barrier function, produce cerebrospinal fluid
line brain ventricles and the central canal of the spinal cord
what are the glial cells of the central nervous system
astrocytes
microglia
ependymal cells
oligodendrocytes
what is the function of oligodendrocytes
form the myelin sheath around neurons in the cns and provide structural support
what is the function of satellite cells
regulate the chemical environment and help in repair of the PNS
wrap around cell bodies in the PNS
what is the function of schwann cells
form a myelin sheath around neurons in PNS
wrap around the axon in a spiral manner
what are the glial cells of the peripheral nervous system
satellite cells and schwann cells
in what direction do sensory afferent nerves go
from receptors to the central nervous system
in what direction do motor efferent nerves go
away from the central nervous system to effectors
what are the types of motor efferents
somatic and visceral
what do somatic motor efferent nerves involve
voluntary muscle contraction
what do visceral motor efferent nerves involve
these constitute the autonomic nervous system as it is involuntary
how many pairs of spinal nerves are there
31
what are dermatomes
sensory spinal nerves
what are myotomes
motor spinal nerves
how many pairs of spinal nerves are in the cervical region
8
how many pairs of spinal nerves are in the thoracic region
12
how many pairs of spinal nerves are in the lumbar region
5
how many pairs of spinal nerves are in the sacral region
5
how many pairs of spinal nerves are in the coccygeal region
1
what is the organisation of white and grey matter in the spinal cord
white matter on the outside and grey matter on the inside
where does the spinal cord lie
within the vertebral canal
what are the meninges that cover the spinal cord
dura matter
arachnoid matter
pia matter
what does the dorsal horn of the spinal cord control
sensory
what does the ventral horn of the spinal cord control
motor
what is found within the white matter
myelinated axons
what is found within the grey matter
axons and cell bodies, synapses
how does nerve fibre number change as you go up the body
increases
what is the arrangement of white and grey mattter in the brain
grey on the outside and white on the inside
what protects the brain
the skull
are meninges found in the brain
yes
describe the layers of protection from scalp to brain
- scalp
- skull
- periosteal dura mater
- meningeal dura mater
- arachnoid mater
- subarachnoid space
- pia mater
- brain
where is the thalamus in the brain
in the middle, above the pons
where is the pons
next to cerebellum, above the medulla oblongata
what is the pituitary gland
under the hypothalamus
where is the hypothalamus
below the thalamus
what are the lobes of the brain
frontal
parietal
temporal
occipital
what makes up the brain stem
the mid brain and hind brain
what is found in the forebrain
cerebrum and diencephalon
what is the found in the hindbran
pons, medulla, cerebellum
what is the cerebrum in control of
motor and sensory
language
memory
perceptions
emotion
what is the diencephalon
the thalamus and the hypothalamus
what does the thalamus do
relay sensory and motor signals
what does the hypothalamus do
regulate homeostasis, hormones and emotions
what does the midbrain do
control visual and auditory reflexes, and pain
what does the medulla do
regulate breathing, heart rate, blood vessels
what does the cerebellum do
balance and posture
what does the autonomic nervous system control
cardiac muscle
smooth muscle
some glands like the adrenal gland
where is the synapse on the sympathetic ganglion
on the sympathetic chain in thoracic 1 to lumbar 2 or on the adrenal medulla
where is the synapse for parasympathetic ganglions
near the target organ
which branch of the autonomic nervous system has slowing effects
parasympathetic
which branch of the autonomic nervous system has fast effects
sympathetic
what are the parasympathetic nerves
- cranial
- sacral
what are the cranial nerves with parasympathetic ganglion
3, 7, 9 and 10
ie
- oculomotor
- facial
- glossopharyngeal
- vagus
what does the facial nerve control parasympathetically
submandibular and sublingual salivary glands
what does the glossopharyngeal nerve control parasympathetically
the parotid gland
what does the vagus nerve control parasympathetically
heart
gastrointestinal tract
bronchi
what are the parasympathetic sacral nerves
S2, 3 and 4
what do the S2, 3 and 4 nerves supply parasympathetically
the pelvic organs
which section of the spinal cord has sympathetic control
thoraco to lumbar, from T1 to L2
what is controlled by the thoraco lumbar region of the spinal cord
heart
blood vessels
bronchi
gastrointestinal tract
adrenal medulla
what are the two receptors found on the autonomic nervous system
adrenergic and cholinergic
describe the types adrenergic receptors
alpha one
beta one
beta two
what does the alpha one adrenergic receptor function to do
smooth muscle contraction
what does the beta one adrenergic receptor function to do
increase in rate and force of heart contraction
what does the beta two adrenergic receptor function to do
smooth muscle relaxation
what are the types of cholinergic receptors
muscarinic and nicotinic
what do muscarinic cholinergic receptors do
post ganglionic atropine antagonist
what does nicotine function to do
pre and post ganglionic synpases and the neuromuscular junction
what is the effect of parasympathetic neurons on salivary glands
high volume and low viscosity (serous)
which type of receptor is involved in the vasoconstriction of blood vessels
alpha one adrenergic receptors
which receptor is involved in an increase in heart rate and force of contraction
beta one adrenergic
what is polarisation
difference in voltage between intracellular fluid and extracellular fluid
what is the average neuron membrane potential
-70
describe the process of action potential generation
- stimulus causes sodium channels to open
- influx of sodim ions
- depolarisation as threshold of -55 is reached
- this triggers opening of voltage gated sodium channels across the axon of the nerve to create a wave of depolarisation
- membrane potential reaches -35
- this triggers sodium channels to close and voltage gated potassium channels to open
- repolarisation
- sodium potassium pump aids achievement of resting membrane potential
what is the refractory period
the period where another action potential cant be generated
when can a new action potential be generated
when the first is completed
how does axon size affect impulses
larger axons have faster impulses because their larger plasma membrane has more ion channels
are autonomic sensory nerves myelinated
not a lot, usually thin or nothing
are alpha motor neurons myelinated
yes
how does autonomic neuron cell differ to motor
autonomic is thinner
how does neurotransmitter pass between synapses
- action potential arrives at the axon terminal
- voltage gated calcium channels open
- calcium enters the cell
- calcium signals to vesicles
- vesciles move to the membrane
- docked vesicles release neurotransmitter by exocytosis
- neurotransmitter diffuses across the synaptic cleft and binds to receptors
- transmitter reuptake into presynaptic cell, transmitter destruction by enzymes
