Lecture 4 Flashcards
What is the nervous system divided into?
CNS and PNS
What does the CNS consist of?
Brain and spinal cord.
What does the PNS consist of?
Nerve fibres carrying information between the CNS and other parts of the body.
Where are most of the neuronal cell bodies located?
The CNS.
What is the PNS subdivided into?
afferent
efferent
What do the afferent nerves do?
Cary information from the sensors to the CNS.
What do efferent nerves do?
Cary information from the CNS to effector organs.-
What are the two components of the efferent nervous system?
The autonomic system
The somatic system
What does the autonomic system do?
Nerve fibres innervate smooth muscle, cardiac muscle , glands, some motor organs and some immune organs. (no conscious control)
What two sections is the autonomic system divided into?
Sympathetic and parasympathetic.
What does the somatic system do?
- consists of fibres of the motor neurons that supply skeletal muscle
- conscious control
- also controls reflexes
What are the three classes of neurons?
Afferent, efferent, interneurons
Where are most of the afferent and efferent neurons?
PNS
Where are the interneurons located?
CNS
Are most visceral organs innervated by sympathetic and parasympathetic nerves?
Yes.
How do the parasympathetic and sympathetic systems interact?
They both affect most organs, in opposite ways. Both increase and decrease the activity in some.
Which system (sympathetic or parasympathetic) dominates the fight or flight response?
Sympathetic.
Which system (sympathetic or parasympathetic) dominates the rest and digest phase?
Parasympathetic-
What are the four major types of glial cells?
1 astrocytes
2 oligodendrocytes
3 ependymal cells
4 microglia
What are astrocytes?
- most abundant glial cells
- hold neurons together
- guide them in fetal development)
- help in establishing the blood brain barrier
- nutrient transport
- repair of injury
- basically take care of the neurons
What are oligodendrocytes?
-glial cells that create myelin sheaths
What are the ependymal cells?
Glial cells that line the internal cavities of the CNS
- contributes to the formation of CSF
- stem from which more glial and neural cells can emerge
- control what goes in and out of the brain
What are the microglia?
-the immune system of the CNS
What layers protect the CNS?
- cranium (skull)
- the meninges- dura, arachnoid and pia mater
- CSF
- blood/brain barrier
What layers protect the PNS?
- spinal column
- meninges (pia and dura)
What are the functions of CSF?
- protection of the brain
- exchange of material between the neural cells and the interstitial fluid (not blood)
What is the role of astrocytes in the blood brain barrier?
Form tight junctions in between the capillaries so only way through is through the capillaries themselves not in between.
What substances diffuse easily across the blood brain barrier?
CO2, O2, alcohol, anaesthetics and steroid hormones, small water molecules
=passive transport
How are most substances transported across the blood brain barrier?
- Active transport
- transported by selective membrane bound carriers
- glucose (only source of energy)
- amino acids,
- ions (Na+, K+ )
What are the 4 main parts of functional anatomy of the brain?
1.Cerebrum below is 2. Forebrain at the back is 3.Cerebellum 4.Brainstem
What is the cerebrum divided into?
- Frontal lobes
- Parietal lobes
- Occipital lobes
- Temporal lobes
- Basal nuclei
What is the function of the frontal lobes?
-voluntary motor activity
What is the function of the parietal lobes?
-processing sensory information from somatic areas
What is the function of the occipital lobes?
-visual information
What is the function of the temporal lobes?
-auditory information
What is the functions of the basal nuclei?
-action selection
Which parts of the brain have a role in cerebral connections?
- thalamus
- hypothalamus
- limbic system
What is the function of the thalamus?
- relay station
- important in motor control
What is the function of the hypothalamus?
-integration center for homeostatic functions
What is the role of the limbic system?
-animal motivation and memory
hippocampus and amygdala
What is the EEG?
electroencephalography
- electrodes on head= see electric activity depending on which part of the brain are active
- pain detection (before slaughter)
What are the cerebral functions?
- learning
- memory-information/response processing
What is the function of the cerebellum?
- balance /eye movements)
- organisation of voluntary movement (the patterns)
- gaits
Describe cerebral hypoplasia in cattle.
- when cerebrum dies off
- animal can’t move well as its motor areas are gone
What is the function of the brain stem?
- vital visceral regulation
- cranial nerves
- sleep (anaesthesia)
- relay center between the PNS and CNS
Cranial nerve 12.
Hypoglossal
What is part of the spinal cord?
- meninges
- CSF
- Afferent tracts
- Efferent tracts
- spinal reflexes
What is the small circuit involving the reflexes like?
Afferent neuron- interneuron- efferent neuron
Describe Wobbler syndrome in horses.
-damage to spinal cord= instability of vertebrae= pinching of spinal nerves
-you know where your leg is, the horse doesn’t
= very hard to coordinate
