Chapter 4- Devisions Of The Nervous System Flashcards
What is the CNS
Central nervous system
Spine and brain
What is the PNS
Peripheral nervous system
Is made of the nerves that connect the CNS with the receptors on muscles and glands
What nerves make up the PNS
- Ganglia
- Cranial nerves( mixed nerves, sensory and motor )
- Spinal nerves
- Ventral root
- Dorsal root
- Dorsal root ganglion
What are cranial nerves?
- 12 Pairs in the brain
- Mixed nerves: Carry information into and away from the Brain
- Example: Optic nerve and auditory nerve
- Only some are sensory and motor: Sensory carry impulses to CNS, motor carry impulses away
What is a ganglia?
- Nerve rivers are arranged into nerve cell bodys out side the CNS
What are spinal nerves?
- There are 31 pairs in the spinal cord
- All mixed nerves
- Joined together by 2 roots
What is the ventral root?
- Contains axons of motor neurons that have their cell body’s in gray matter in the spinal cord
What is the dorsal root?
Contains acorns of sensory neurons that have their cell bodies in small swellings of the dorsal root ganglion
What is the affront/sensory division
- Carries impulses into the CNS
- Divided into somatic and visceral
- Somatic sensory: Nerve cell receptors in the skin and around muscles and joins
- Visceral sensory: Nerve cells that take impulses from internal organs
What is the efferent division
Carries impulses away from CNS
Divided into: Somatic and autonomic
Autonomic divided into sympathetic and parasympathetic
What does the somatic division
- Apart of efferent division
- Carries messages to the skeletal muscle
What is the autonomic division?
- Carries messages to the heart and involuntary glans
- Divided into sympathetic and parasympathetic
What does the autonomic division do?
Effects: Heart, involuntary muscles, glands
Function: Adjusts internal environment
Efferent:Two nerve fibres from the CNS with the synapse in a ganglion
Neurotransmitter: Acetylchlorice/ noradrenaline
Control: involuntary
Effect: Excitation or inhibition
Nerves to target organ: Two sets’ Sympathetic and parasympathetic
What does the somatic division do?
Effectors: Skeletal muscles General function: responded to external Efferent: One nerve fibre from the CNS to the effector, no synapses or ganglion Neurotransmitter: Acetylcholine Control: Voluntary Nerves to target organ: One set Effect on target organ: excitation
What effects does the sympathetic division have when stimulated.
- Tends to produce a response that prepares the body for strenuous physical activity
- Increase heart rate
- dilates bronchioles
- Decreases stomach movement
- Dialates pupil
- Increases sweat glands
- Increases hormone secretion in adrenal medulla
How many pairs of nerves arise from the brain and spinal cord?
- 12 pairs of cranial laws
- 31 pairs of spinal nerves
What is a mixed nerve?
Has booth sensory and motor fibres, allowing the nerve to carry impulses to and from the CNS
On what sort of never would you find a ventral and dorsal root?
- Spinal nerves are joined to the spinal cord by the ventral and dorsal root
- Located where the spinal cord joins the spinal nerves
- Ventral has axons of motor neurones with cell bodies connected to the grey matter
- Dorsal root have the axon of sensory neurones with cell Body connected to the dorsal root ganglion
What would happen if the ventral root was damaged
It would effect the motor functions because the ventral root contains motor neurons connected to the spinal nerve
Difference between efferent and afferent divisions ?
The afferent division has fibres that carry impulses to the CNS
The efferent division has fibres that carry impulses away from the CNS
What is the relationship between the autonomic nervous system, the efferent division and peripheral division?
- Peripheral includes everything outside the brain and spinal cord
- Efferent is made up of the nerves that carry messages from the brain and spinal cord to muscles
- Autonomic carries impulses to the to involuntary glands and muscles
What is the difference between the sympathetic and parasympathetic divisions of the autonomic nervous system?
- Parasympathetic produces responses that maintain the body during quiet conditions
- Sympathetic division produces responses that prepare the body for strenuous physical activity (fight or flight)
Four responses caused by fight or flight
- increased heart rate
- dilation of airways in the lungs
- increased rate and depth of breath
- increased secretion from sweet glans
- Rise in blood and glucose level
- Release from adrenal medulla of the hormones which intensify other responses
Differences between the action of nerves and hormone; transportation
- Nervous response: nerve impulses travel rapidly along the nerve fibres
- Hormones: are slower as they are transported by the bloodstream
Difference between the action or nerves and hormones: Response
Nerve impulse; immediate response, only lasts for a short time
Hormone’ Typically slower response, but lasts longer
Difference between the action or nerves and hormones: Messages
Nerve impulses; electrochemical change that travel along the membrane of a neuron
Endocrine messages; are hormones, chemical substances
Difference between the action or nerves and hormones: effect
Nerve impulses travel along a nerve fibre to a specific part and only influence just one effector
Hormones travels along all parts of the body, carried by blood and can affect a number of different organs
What are some similarities between the nervous and endocrine system
- Noradrenaline, antidiuretic, dopamine function and hormones and neurotransmitters
- Neurones secrets hormones such as oxytocin and adrenaline
- Some neurotransmitters have the same effect on target cells
