Ch. 4 Divisions of the Nervous System Flashcards
What is the purpose of the NS
receive + process information from sense organs + bring about responses to the received information
What are the two main divisions of the nervous system, and what dose each contain
- Central Nervous System
- Control center
- Consists of: Brain and Spinal Chord - Peripheral Nervous System
- Nerves that connect the CNS with receptors, muscles + glands
- Consists of:
a. Nerve fibres > carry information to and from CNS
b. Groups of nerve cell bodies (ganglia) > lie outside brain + spinal chord
What are the two types of nerves of the PNS, and how many of each type do we have
Cranial 12 pairs (arise from brain) and Spinal 31 pair (arise from spinal chord)
What are mixed nerves
o =contain fibres that carry impulses to and from brain
what are the two nerves called that carry info to and from brain
- Fibres that carry impulses to CNS= sensory fibres
- Fibres that carry impulses from CNS= motor fibres
How are each spinal nerve joined to the spinal chord
two roots- ventral and dorsal
Explain the ventral root
- Contains axons of motor neurons that have their cell bodies in grey matter of spinal chord
explain the dorsal root (and ganglia)
- Contains axons of sensory neurons that have their cells bodies in a small swelling on the dorsal root = dorsal root ganglia
What are the two main division of the PNS
Afferent (into CNS) and Efferent (away from CNS)
What are the two divisions of the Afferent NS
- somatic (skin and muscles)
2. visceral (internal organs)
What are the two divisions of the Efferent NS
somatic (to skeletal)
autonomic (to involuntary muscles)
What are the two divisions of the autonomic NS
sympathetic
parasympathetic
What is the autonomic NS regulated by
o Groups of nerve cells in the medulla oblongata, hypothalamus + cerebral cortex
What are the 6 areas of difference of Autonomic and somatic NS
effectors general functions efferent pathways neurotransmitter nerves to target area effect on target area
What are the difference in general function of the Autonomic NS and Somatic NS
A- homeostasis
S- response to external environemtn
What are the difference in efferent pathways of the Autonomic NS and Somatic NS
A- two neutrons with synapse in ganglion
S- one neuron
What are the difference in effectors of the Autonomic NS and Somatic NS
A- involuntary
S- voluntary
What are the difference in neurotransmitter of the Autonomic NS and Somatic NS
A= acetylcholine or noradrenaline
S= acetylcholine
What are the difference in nerves to target area of the Autonomic NS and Somatic NS
A= two sets (para/symp)
S=one set
What are the difference in effect on target area of the Autonomic NS and Somatic NS
A= excitation or inhibition
S=always excitation
Define parasympathetic/ sympathetic
- Parasympathetic- generally produces responses that maintain body during quiet conditions
- Sympathetic- generally produces responses that prepare body for strenuous activity
o Often called fight-or-flight response
When a message from autonomic nerves> muscles + glands= carried by which neurotransmitter at nerve endings from Para/sympathetic
para= acetylcholine
sym= noradrenalin
What are some organs that the para/sympatheic systems affect
Heart- rate and stregth Lungs- dilate/constrict bronchioles Stomach- movement increase decrease Iris- dilate, constrict Salivary glands Blood vessels bladder adrenal medulla
what are three organs that while the sympathetic division has effect, the para does not
sweat glands, blood vessels, adrenal medulla
Define flight or fight/ alarm reaction response
response that prepares body for increased activity; brought about by stimulation of sympathetic division of the ANS
What are three similarities of the hormonal and nervous system
- some substances act as both hormones + neurotransmitters (dopamine, acetylcholine, noradrenaline)
- some hormones (oxytocin + epinephrine) are secreted by neurons into extracellular fluid
- some hormones/neurotransmitters= same effect on same target organs e.g. norepinephrine + glucagon= liver cells to make glycogen > glucose
what are the 8 characteristics of differences of the nervous and hormonal systems
Nature of message (electrical/ hormone)
Transport of message (membrane/blood)
Cells effected (muscles glands/ all)
Type of response (local and specific/ general and wide)
Time taken (fast/ slow)
duration (brief/ long lasting)
