X Neuro: Mrs Grant (Adult Health, Chp 14) Flashcards
The Nervous system works together with what system?
The Endocrine system to maintain homeostasis
NS responsible for what in the body?
- communication
- control
- It interpretes info received then send to appropriate areas of the brain of spinal cord
NS reacts in split seconds while Endocrine (enzymes/hormones) system takes longer to take effect.
.
CNS includes
- brain
- spinal cord
Peripheral Nervous System
- Somatic nervous system
- Autonomic nervous system
Somatic Nervous System (voluntary)
sends messages form CNS to skeletal muscles (voluntary)
(i. e. walking)
- Spinal Nerves: 31 pairs (Afferent, sensory /Efferent, motor)
- Cranial Nerves: 12 pair, (conduct impulses btwn head/neck/brn), back of brain, brain stem. (Nerve X, Vegus brings impuls to Thoracic/abdominal, unlike the rest)
Autonomic Nervous System
involuntary, automatic
sends messages from CNS to smooth muscle, cardiac muscle and certain glands (involuntary, unconscious i.e. heart beat, breathing)
- Sympathetic NS
- Parasympathetic NS
Cells of Nervous System
- Neuron
- Neuromuscular juntion
- Neurotransmitters
- Neurocoverings
- Synapse
Neurons
most important cells in transmission of info
- cell body, nucleus, axon, dendrites
- receive impulses
- many shapes and sizes
- non myotic (don’t replicate when injured. don’t hear of malignancy of these cells because they don’t multiply
Neuromuscular Junction
area of contact btwn ends of fibers
Neurotransmitters
store chemicals
- ACETYLCHOLINE: transmission of impulse (speed)
- NOREPINEPHRINE: maintain arousal, dream, mood
- DOPAMINE: helps with fluidity of mvmt, motor functions (i.e. parkinson’s, lack of dopamine)
- SERATONIN: sleep, temp, mood
Synapse
space btwn 2 neurons. Impulse crosses to next neuron
Neuron Coverings
Myelin Sheath
- white waxy material insulates/protects axon
- starts to form at 4mos gestation
- increases speed of impulse transmission
Neuro Glial Cells
support cells to neurons. ‘Nerve Glue’. Support, insulate, care, nourish neurons
Peripheral NS: Spinal Nerves
- Spinal Nerves: 31 pairs of mixed nerves
- Afferent: sensory, RECEIVE info from organs
- Efferent: motor nuerons, SEND messages from CNS to periphery
Peripheral NS: Cranial Nerves
- 12 pair, attached to brain stem
- conduct impulses btwn head/neck/brn
- all except cranial nerve X, Vegus, brings impulse to Thoracic/abdominal, unlike the rest
Autonomic NS: Sympathetic NS
- work together, but one will dominate the others. Activated in times of severe stress or when threatened.
- Fight or Flight
- If body stays in Fight or Flight state for too long, can cause HTN and illness
Autonomic NS: Parasympathetic NS
- most active during resting state.
- digestion, reproductive funtion
- Feed & Breed
- Paradoxial Fear can result.
Paradoxical Fear
when person knows running or fighting won’t help. Body relaxes. (i.e. urinate or defacate on self, pass out)
- the body’s way of taking you out of the situation.
- Protection, acceptance of situation.
- ‘Bradying down’ –> LO BP, Bradycardia
Effects of Normal Aging on NS
- loss of brain weight (cortex (gray matter) lose cells at higher rate), impairs reasning, memory, language
- loss of neurons (lose 1% neurons after age 50)
- reduction cerebral blood flow
- LO brain metab and O2 utilization
- LO blood supply to spinal cord, dec reflexes
- altered sleep/wake ratio
- LO ability to regulate body temp
- LO velocity of nerve impulses
- Existing neurons may contain 1)Senile Plaques 2) Neurofibroloary tangles, 3) Age pigment (Lipofuscin)
Brain
- Cerbrum
- Diencephalon
- Cerebellum
- Brain Stem (mid brain, pons, medulla oblongata, coverings of brain, ventricles
Can Neurons be replaced/regenerated
NO
Aging: Lipofuscin
name given to finely granular yellow-brown pigment granules[1] composed of lipid-containing residues of lysosomal digestion. It is considered to be one of the aging or “wear-and-tear” pigments, found in the liver, kidney, heart muscle, retina, adrenals, nerve cells, and ganglion cells. It is specifically arranged around the nucleus, and is a type of lipochrome.
Aging: Senile Plaques
polymorphous beta-amyloid protein deposits found in the brain in Alzheimer disease and normal aging. This beta-amyloid protein is derived from a larger precursor molecule of which neurons are the principal producers in brain.