Nervous System 2 Flashcards
What’s the main regulatory system of the nervous system ?
1- sense environment
2- Transfer information centrally for processing
3. Respond
How are singe celled organisms nervous system evolved ?
-There brain is the nucleus
- Communication ( with other organelles ) via chemical release
How are multicellular organisms nervous system evolved ?
- Brain = network of intercommunicating nerve cells which is the nerve net
- Communication between cells - specialised into different functions e.g secretion, movement, defence
What are most animals that have distinct front and back ends ?
Most animals are bilaterally symmetrical around the midline, with distinct front and back ends
Where are sensory receptors clustered ?
Towards the front end (direction of movement )
What do the neurones that supply the sensory cluster grouped together form ?
The brain
What is segmentation in longitudinal centralisation ?
Aggregation of nerve cell bodies as individual ganglia in most segments
How does longitudinal centralisation affect co-ordination ?
The function of the body segment within that region
Neuronal cell bodies along the length of the body not all at the head.
What’s the function of the brain like in longitudinal centralisation ?
Decentralized due to neuronal cell bodies being along the length of the body. Neurones projecting to and from each ganglion.
What are the 3 broad types of neurones ?
- AFFERENT NEURONES
- Information flow via axon towards control centre - EFFERENT NEURONES
- Information flow via axon away from control centre - INTERNEURONES
- Central connections
What increases with interneurones and synapses ?
Increase complexity
What are the 3 types of neurones ?
1- UNIPOLAR
- Branched axon
- No dendrites
2- BIPOLAR
- Axon and a dendrite
3- MULTIPOLAR
-Axon and several dendrites
What are the 2 main anatomical divisions ?
- CENTRAL NERVOUS SYSTEM
- Brain
- Spinal cord - PERIPHERAL NERVOUS SYSTEM
-Everything outside CNS
- Afferent (sensory ) neurone
- Efferent ( motor ) neurones
- Axons of these run together as peripheral nerves.
What are the 12 pairs of cranial nerves On Old Olympus Towering Top, A Friendly Viking Grew Vines And Hops?
I = olfactory
11 = optic
iii = oculomotor
iv = trochlear
v = trigemenial
vi = Abducens
vii = Facial
Viii = vestibulocochlear
ix = Glossopharyngeal
x = vagus
xi = accessory
xii = hypoglossal
What are the two main functional divisions of the peripheral nervous system ?
SOMATIC NERVOUS SYSTEM
- Afferents from skin, joints, muscles
- Efferents to skeletal muscle
- Posture, movement, reflexes
DETECTS AND RESPONDS TO EXTERNAL ENVIRONMENT
AUTOMATIC NERVOUS SYSTEM
- Afferents from internal organs
- Efferents to smooth/cardiac muscle and glands
- Control endocrine function and homeostasis
DETECTS AND RESPONDS TO INTERNAL ENVIRONMENT
What are 4 external events that sensory neurones can detect ?
- touch
- Temp
- Pain
- taste
What are 4 internal events that the sensory neurone can detect ?
- Blood pressure
- Blood volume
- Osmolatility
- Temperature
what occurs when a sensory receptor detects an event ?
Leads to an action potential in afferent neurones which are conducted to the CNS
What are the features of a somatic response ?
- Skeletal muscles
- Voluntary control
- Rapid and precise
- Mainly to affect external events
What are features of an autonomic response ?
- Internal organs - smooth muscles and glands
- Involuntary
- Rather slow
- For control of internal systems
What is a motor response due to ?
Due to action potentials in efferent neurones arising from the CNS
What’s the two subdivisions of the automatic nervous system ?
SYMPATHETIC - Flight or fight
PARASYMPATHETIC - Rest and Digest which is more selective
What’s the anatomy of the sympathetic and parasympathetic nervous system 1. CNS location
2. Pre-ganglionic
3. Post-ganglionic ?
SYMPATHETIC
1. Thoraccolumbar SC
2. Short
3. Long
PARASYMPATHETIC
1. Medulla and Sacral SC
2. Long
3. Short
What’s the pharmacology for the sympathetic and parasympathetic nervous system
1. Pre-ganglionic
2. Post-ganglionic ?
SYMPATHETIC
1. Acetylcholine
2. Noradrenaline
PARASYMPATHETIC
1. Acetylcholine
2. Acetylcholine
What’s the function of the Afferent ( sensory ) neurone and efferent ( motor ) neurone ?
To produce a response to stimuli respectively
What divisions is the control of the ANS through ?
Sympathetic and parasympathetic divisions
