Chapter 3 And 4: The Nervous System Flashcards
Identify the main divisions of the nervous system.
Flowchart
Differentiate between the CNS and the PNS.
The CNS consists of the brain and spinal chord whereas the PNS includes ALL nervous tissue and transmits impulses(and therefore information) to and from the CNS
Sensory neurons
Carry messages from receptors in the sense organs or skin, to the CNS(brain and spinal chord).
Motor neurons
Carry messages from the central nervous system to the muscles and glands — the effectors.
Interneurons(association neurons)
Located in the CNS and are the link between the sensory and motor neurons. Also known as relay neurons
Some components of the PNS
- Nerve fibres which carry information to and from the CNS.
- Groups of nerve cell bodies called ganglia which lie outside the brain and spinal chord.
- 12 pairs of cranial nerves and 31 pairs of spinal nerves which contain fibres carrying impulses to and from all parts of the body.
Cranial nerves
12 pairs of nerves that arise from the brain
Afferent division
the sensory division of the PNS; consists of fibres that carry impulses INTO the CNS.
These impulses are carried to the CNS by the sensory nerve cells from receptors in the skin and around the muscles and joints.
These nerve cells from the body are called somatic sensory neurons.
Efferent division
Has fibres that carry impulses AWAY from the CNS.
Sensory fibres
Fibres that carry impulses INTO the CNS
Motor fibres
Fibres that carry impulses AWAY from the CNS
Ventral root
Contains the axons of motor neurons that have their cell bodies in the grey matter of the spinal chord.
What are the effectors of the autonomic division?
Heart muscle, involuntary muscle, glands
What are the effectors of the somatic division of the peripheral nervous system?
Skeletal muscles(voluntary)
What is the general function of the autonomic division of the PNS?
Adjustment of the internal environment(homeostasis).
What is the general function of the somatic division of the PNS?
Response to the external environment
What is the efferent pathway of the autonomic division?
Two nerve fibres from the CNS to the effector with a synapse in a ganglion.
What is the efferent pathway to the somatic division?
One nerve fibre from the CNS to the effector; no synapse, no ganglion
What is the neurotransmitter of the autonomic division at the effector?
Acetylcholine or noradrenaline
What is the neurotransmitter of the somatic division at the effectors?
Acetylcholine
Is the autonomic division voluntary or involuntary?
Usually involuntary
Is the somatic division voluntary or involuntary?
Usually voluntary
How many sets of nerves to the target organs of the autonomic division?
2 sets — Sympathetic and Parasympathetic
How many sets of nerves to the target organs of the somatic division?
One set
What effect does the autonomic division have on the organ?
Excitation or inhibition
What effect does the somatic division have on the organ?
Always excitation
Name 10 structures of the sympathetic and parasympathetic nervous system
Heart Lungs Stomach — Intestines Liver Iris of the eye Sweat glands Salivary glands Blood vessels of: skin, skeletal muscle and internal organs Urinary bladder Adrenal medulla
Name 10 functions of the sympathetic nervous system (of the structures).
- Increased heart rate and strength of contraction
- Dilates bronchioles in the lungs
- Decreased movement in the stomach; intestines
- Increase the breakdown of glycogen and release of glucose in the liver.
- Dilates pupils of the iris of the eye
- Increases sweat secretion in the sweat glands.
- Decreases secretion of saliva from the salivary glands.
- Constricts blood vessels in the skin and internal organs, dilates blood vessels in the skeletal muscle.
- Relaxes muscles of the wall of the urinary bladder
- Stimulates hormone secretion in the adrenal medulla.
Name 10 functions of the parasympathetic nervous system.
- Decreased heart rate and strength of contraction
- Constricts bronchioles in the lungs
- Increases movement in the stomach; intestines
- Increases uptake of glucose and synthesis of glycogen.
- Constricts pupils of the iris of the eye
- Has no effect on sweat secretion in the sweat glands.
- Increases secretion of saliva from the salivary glands.
- Little effect on the p blood vessels in the skin and internal organs, no effect on the blood vessels in the skeletal muscle.
- Constricts muscles of the wall of the urinary bladder
- No effect in the adrenal medulla.
What are the subdivisions of the efferent nervous system?
Somatic sensory neurons from skin and muscles.
Visceral sensory neurons from internal organs.
