peripheral nervous system- motor division

what are the functions of the autonomic nervous system

to monitor heart rate, blood pressure, body temperature, digestion, release of energy, pupil diameter, air flow to lungs, dedication and urination.

what is the motor division of the peripheral nervous system?

is the system that carries impulses away from the central nervous system

what is the somatic motor division?

is the part of the motor nervous system that takes impulses from the central nervous system to skeletal muscle to cause contraction, muscle tine and movement.

which division of the motor peripheral system is under voluntary control?

the somatic division

what are the two divisions of test motor system

somatic and autonomic

what is released into the synapses by the somatomotor division?

Acetylcholine (ACh)

why is acetylcholine released by the somaticomotor division?

to stimulate muscle contraction

what is the structure of the somatic division of the motor peripheral system?

the cell bodies are in the central nervous system (in spinal cord grey matter) and their axons extend from the central nervous system all the way up to the muscles. there is no intermediate synapses or ganglia

how many motor neurons carry an impulse to an effector in the somatic division?

there is one 1 motor neuron (no intermediate steps)

how many motor neurons carry an impulse to an effector in the autonomic system?

2 motor neurons

what is the role of the autonomic motor nervous system?

it carries impulses from the central nervous system to the heart muscle and other muscles of internal organs and the glands. this is to adjust and keep control of the internal environment (homeostasis)

is the autonomic motor nervous system under voluntary control?

no

how is the autonomic division of motor neurons further divided up?

into the sympathetic and the parasympethetic divisions

most organs under autonomic control receive two sets of nerve fibres ….

the symethetic and parasympathetic fibres

what is the sympathetic autonomic motor division?

the “fight or flight” response.

what is the sturucture of the sympathetic autonomic motor division?

the ganglia is closer to the Central nervous system as this reaction needs to be faster. At first Acetylcholine is released at the first synapse, then noradrenaline is released at the next.

what is the difference between the structure of the sympathetic and the parasympathetic divisions?

in the sympathetic division the ganglia is closer to the central nervous system (as fight or flight reaction needs to be fast), In the sympathetic nervous system the sympathetic fibres emerge from the ventral roots of most spinal segments whilst the parasympathetic nerve fibres mostly emerge from the brain and the base of the spinal cord, dont often come from ventral roots of the segments of the spinal cord

what is the role of the parasympathetic division?

“rest and digest”

is the ganglia closer in the sympathetic or parasymepetic division?

sympathetic

what neurotransmitter is releaseed that synapses and tissues of the parasympathetic fibres?

ACh (Acetylchlorine)

what is the pathway for the autonomic nervous system?

the ner e impulse travels along two neurons from the central nervous system to an organ controlled by the autonomic nervous system.

are the neurions in the parasympathetic system myelinated?

the first neuron is, the second is not

where is the first cell body in the parasympathetic nervous system?

in the central nervous system

where is the second cell body in the parasympathetic nervous system?

outside the central nervous system inside a ganglion

sympathetic and parasympathetic systems usually…

balance each other out to maintain homeostasis

each target tissue has…

both sympathetic and parasympathetic neuron supply,

what is the purpose of the sympathetic nervous system?

to prepare the body for strenuous physical activity

what happens in a threatening situation?

the sympathetic division becomes dominant, causing a fight or flight response all to prepare the body for increased activity and rely on the skeletal muscles producing movement and an increased level of alertness to think and act quickly.

how is the sympathetic nervous system provoked?

by fear, anger, stress, danger, or competition.

describe what happens in a fight or flight response

blood glucose levels rise as the liver converts more glycogen into glucose. secretion of sweat glands increase, adrenal medulla releases hormones adrenaline and noradrenaline to intensify and prolog the responses, the rate and force of contraction of heart will increase with a consequent rise in blood pressure. blood vessels dialate in organs involved in organs involved in strenuous activity (e.g skeletal muscles, heart and liver), blood vessels will constrict in organs not involved in activity (e.g kidney, digestive tract and skin) and airways and lungs will dilate and rate and depth of breathing increases

what is the parasympathetics role in rest and digest?

it is for quiet conditions, like when at rest the parasympathetic nerves are sending impulses to internal organs to maintain stability of bodily functions (e.g to bring down resting heart rate from approx 100 beats per min to 70 beats per minute)

what is a reflex?

is a rapid, automatic response to a change in the external or internal environment

refelxes involve what organs?

(sometimes) the unconscious part of the brain, but mostly coordinated by the spinal cord.

what is a reflex arc?

the reflex is carried out by the spinal cord alone and is a spinal reflex. the pathway of a nerve impulse is coming into the spinal cord from the receptor, the impulse may be passed to motor neurons at some level of control or to may travel up a few segments up or down the spinal cord before travelling out through a motor neuoron

what is another word for a reflex arc?

a spinal reflex arc

how does is a reflex involuntary?

it does not involve the brain, impulses may be sent to the brain, so that we become aware of what is happening. However this awareness does not occur until after the response has been initiated

what are the four properties of a reflelx is…

stimulus is required for a reflex- it is not spontaneous, reflex is involuntary and occurs without a concious thought, a reflex is rapid- only a small number if neurond are involved and a reflex is stereotyped - it occurs in the same way each time.

what are some common reflexes?

saliva in response to sight, smell and taste of food, ejaculation of semen and responses brought about by the autonomic nervous system

what is a a receptor?

a receptor (end of a sensory neuron, or specialised cell that transmits to a sensory neuron) will react to a change in interanl or external environment by initiating a nerve impulse in sensory neuron.

what is an effector?

receives the nerve impulse and carries out the appropriate response. effectors could be muscle or secetatory cells.

function of refelxes?

to protect the body from stimulus, maintain homesostasis, withdrawal from painful stimulus, blinking when something toches corna of the eye, sneezing, coughing (when somthing irritates the nose/ trachea) constriction of pupil in response to light.

what are innate reflexes?

they are present in the brain and or appear during development. automatic and they ate not learned, they are determined genetically.

what are aquired refelxes?

complex motor patterns, learned through repetitions, for example muscular adjustments required to maintain balance while riding a bike.

what are some reflexes?

automatic nervous system responses such as a fight or flight. the patella reflex (knee jerk response) and blink reflex - when someone pokes your eye