Nervous tissue Flashcards
wk 6
What are the three functions of nervous system?
sensory, integrative and motor
describe sensory function of the nervous system.
Receptors detect internal stimuli or external stimuli
Information carried to brain and pinal cord via cranial and spinal nerves
Describe integrative function of the nervous system.
Process information by analysing and making decision about appropriate response= integration
What is the impact of the effector on muscles and glands?
Stimulation of effecter causes muscles to contract and glands to secrete.
Describe the motor function of the nervous system.
After integration: system elicits an appropriate response by activating effectors (muscles and glands)
Though cranial and spinal nerves
What is the input to the CNS from periphery called?
afferent division
what is afferent division stimulated by?
sensory and visceral stimuli
What are the three components of a neuron?
cell body, dendrite and axon
what is the function of the neuron?
are specialised communication cells
What are the two synaptic neurons?
Presynaptic and posy-synaptic
What does a presynaptic neuron do?
sends nerve impulses towards another cell
what does a postsynaptic neuron do?
receives a nerve impulse and responds to it.
What are the three structural types of neurons?
Multipolar, bipolar and unipolar
Where are multipolar neurons found?
Mostly in brain and spinal cord
What are two multipolar neurons and their purpose?
Motor neurons - take action potentials away from CNS
Interneurons (most)
In-between sensory and motor
Where are bipolar neurons found?
in the ear and retina
What are uniploar neurons and what is their function?
sensory receptors: take sensory information towards the CNS
What are the 4 types of Glial cells?
Astrocytes, oligodendrocytes, microglia and ependymal cells
what is the largest and most common cell of the CNS?
Astrocyte
what are the functions of astrocytes?
support neurons
Assist in forming blood brain barrier
Help maintain correct chemical environment
What are Glial cells
Non neuronal cells in the CNS and peripheral nervous system
Don’t produce electrical impulses
what is the function of Oligodendrocytes?
Form and maintain myelin sheath around axons
what are microglia and their purpose?
phagocytes
Remove cellular waste and debris
what structural features do ependymal cells have?
microvilli and cilia
What is the function of epidenymal cells?
produce spinal fluid and assist in moving it around
What is the structure of the blood brain barrier?
endothelial cells of capillaries and astrocytes held together by tight junctions
what are the two functions of the blood brain barrier?
Protects
-brain cells from substances and pathogens
Selective barrier
-prevent passage of substances into brain blood
What is the function of Shawn cells?
Form and maintain myelin sheath
Involved in axon regeneration
in PNS
what are the two functions of satellite cells?
Supports neurons
Regulate flow of materials into cell bodies
Where do satellite cells reside and what are they a precursor to?
Between external lamina and sarcolemma
Precursor to skeletal muscle cells
What does myelination allow for?
This insulates the axons and speed
What is grey matter?
Collection of neuronal cell bodies
What is white matter and why?
Bundles of axons (give a white appearance when myelinated)
Where is the spinal cord? Why?
Inside vertebral column
This allows for protection and support
What are the 3 protective connective tissues that enclose the spinal cord and brain?
Dura, Arachnoid and pia mater
Describe the Dura Mater
Outermost layer
Thick and tough
What and where is the subdural space?
between the dura and arachnoid mater
contains interstitial fluid
describe the Pia mater
innermost layer and transparent
What and where s the sub aracnoid space?
between arachnoid and pia mater, has cerebral fluid
What is a nerve?
Bundle of axons in peripheral nervous system
What are each axons enclosed by?
endoneurium
What wraps up each fascicle?
perineurium
What wraps up the whole nerve?
epineurium
why are nerves organs?
they contain more than one type of tissue
What are the two types of nerves?
Spinal and cranial
Describe the patellar (stretching) reflex.
Stretching stimulates sensory receptor (muscle spindle)
Sensory neuron becomes excited
(in integrating centre) sensory neuron activates motor neuron
Motor neuron becomes excited
Effector (on the same muscle) contracts and relieves the stretching
What are the four major regions of the brain?
Cerebrum, Diencephalon, brain stem and cerebellum
What are the 5 lobes of the cerebrum?
Frontal, parietal, occipital, temporal and insula
Which lobe is responsible for motor actions?
Frontal
Which lobe is responsible for sensory actions?
parietal
Which lobe is responsible for visual actions?
Occipital
Which lobe is responsible for auditory and language actions?
temporal
which lobe is resposnible for taste and memory?
insula
what is the output system?
efferent division
What is the somatic nervous system?
Skeletal system: voluntary movement controlled by neurons
Which efferent division is involuntary?
Autonomic nervous system
What are the two systems of the autonomic nervous system?
Sympathetic and parasympathetic
What does the sympathetic nervous system do?
Flight and fight for a survival system
Turns down systems that don’t need (digestion)
What does the parasympathetic nervous system do?
rest and digest system
Kicks in after the threat is gone to bring us back to homeostasis
rediverts blood back to the digestive system
What do the sympathetic and parasympathetic nervous systems feed into?
smooth muscle, cardiac muscle and glands.
What are the two main types of neurons ?
Multipolar (motor) and unipolar (sensory)
How many pairs of spinal nerves are there?
31
Which types of nerve carries motor and sensory axons?
spinal nerves
What is the role of the cerebellum
smooths and coordinates skeletal muscle
posture and balance
What is the role of the thalamus?
relays sensory input to cerebral cortex
filters what information is important
What is the histological structure of grey matter and why?
highly nucleated (lots of purple dots) because grey matter contains the cell bodies.
Is white matter on the inside or the outside of the spinal cord?
outside- it had the axons so needs to spread the message out.
is a grey matter on the inside or the outside of the brain?
outside
What is the function of astrocytes?
support neurons, assist the formation of the blood-brain barrier and maintain the chemical environment
what is the function of oligodendrocytes?
forms and maintains the myelin sheath
what is the function of microglia and what structure do they have?
remove cellular waste and debris
contains phagocytes.
what is the function of ependymal cells and what structures do they have?
produce spinal fluid and assist in moving the fluid around
microvilli and cilia
What is the function of the cerebellum?
Smooths and coordinates contractions of skeletal
muscles.
Regulates posture and balance. May have role in
cognition and language processing.
What is the function for the thalamus?
Relays almost all sensory input to cerebral cortex.
What is the function of the hypothalamus?
Produces hormones, regulates fluid balance and controls body temperature.
What is the epithalamus?
Consists of pineal gland (secretes melatonin) –
circadian rhythm.
What is the function of the superior colliculi in the midbrain?
coordinate movements of
head, eyes, and trunk in response to visual
stimuli
What is the function of inferior colliculi in the midbrain?
coordinate movements of head,
eyes, and trunk in response to auditory stimuli.
What is the main function of Pons?
Respiration (together with the medulla) helps
control breathing.
*Convey ascending and descending information
What is the function of the medulla oblongata?
regulates heartbeat and blood vessel diameter (cardiovascular centre)
What does the frontal lobe control?
motor
what does the parietal lobe control?
sensory
what does the occipital lobe control?
visual
What does the temporal lobe control?
auditory and language
what does the insula lobe control?
taste memoryPka
What are the three parts of the peripheral system?
Ganglian, spinal and cranial nerves
