Nervous System Flashcards
(26 cards)
cns (central)
brian and spinal cord
pns (peripheral)
nerves outsdie brain and spinal cord.
– Sensory (afferent)
Nerve fibres that carry information to the CNS
- Motor (efferent) division:
Nerve fibres that carry impulses away from the CNS
• Somatic (voluntary)
• Autonomic (involuntary)
– Interneurons (association neurons)
Found in neural pathways in the central nervous system
Connect sensory and motor neurons
neuron (7 parts)
Cell body/Nucleus Dendrites Axons axon terminals Myelin sheath Schwann cells Nodes of Ranvier
Dendrites
– conduct impulses toward the cell body
• Axons
– conduct impulses away from the cell body
• Axonal terminals
– contain vesicles with neurotransmitters
Myelin sheath
– whitish, fatty material covering axons.
• Schwann cells
– Produce myelin sheaths; produce speed.
• Nodes of Ranvier
– gaps in myelin sheath along the axon
nerve impulses
electrical currents (sodium and postasium) charged ions. action potential - transmittion.
regions of the brain
- Cerebrum (cerebral hemispheres)
• Diencephalon (thalamus, pineal, hypothalamus)
• Brain stem (pons, medulla, midbrain)
• Cerebellum
cerebrum
divided into left/right, right controls left, creative and artistic left controls right, logic/rational thinking. hemispheres are divided into lobes: 1. frontal; personality, speech, behav 2. temporal; memory, language 3. parietal; sensations 4. occipital; primary vision
Diencephalon
Sits on top of the brain stem • Enclosed by the cerebral hemispheres • Made of three parts – Thalamus (help interpret sensation) – Hypothalamus (body temperature, water balance and metabolism, regulates pituitary) – Epithalamus (holds pineal gland)
Brain Stem
• Attaches to the spinal cord/ survival mechinisim
Midbrain
(Mostly composed of tracts of nerve fibers, reflex centre for vision and hearing)
Pons
(includes nuclei involved in the control of breathing)
Medulla oblongata • Heart rate control • Blood pressure regulation • Breathing • Swallowing • Vomiting
Cerebellum
- Two hemispheres with convoluted surfaces
* Controls balance/coordination
autonomic nervous system
Regulates functions of the internal systems.
sympathetic; fight or flight
parasympathetic; housekeeping
parasympathetic nervous system
(operates when we are relaxed and conserves energy)
• Conserves energy
• Maintains daily necessary body functions
• Remember as the “D” division
• digestion, defecation, and diuresis
• Decrease heart rate, respiratory rate, blood pressure
sympathetic nervous system
(active during extreme situations such as fear, exercise or rage)
• Response to unusual stimulus
• Remember as the “E” division
• Exercise, excitement, emergency, and embarrassment
• Increases heart rate, blood pressure, breathing, respiratory rate , dilates pupils, opens airways, decreases digestion, decrease urine output
neurotransmitter for somatic nervous system
The autonomic Nervous System uses acetylcholine, adrenalin(epinephrine) or noradrenalin (norepinephrine) as neurotransmitters
meningitis
Inflammation of the meninges (membranes covering brain) usually secondary to another infection and can be caused by • Virus • Bacteria (most serious) • Fungus Untreated is usually fatal. - Signs and symptoms; Fever, Headache, Nausea and vomiting, Stiff neck, Photophobia, Joint aches or pains, Skin rash in some cases (meningococcal meningitis)
stroke
atherosclerosis
thrombus; attached to blood vessle wall
embulos; part of thrombus and detaches and causes blockage.
Disruption to blood flow to the brain causing brain cells in the area to die and may become permanently damaged.
Due to artery being blocked by a blood clot or plaque, or
because the artery breaks or bursts.
Types
1. Ischaemic stroke (blocked blood to tissue in brain. blood vessel in brain)
2. Haemorrhagic stroke (bleed in the brain/aneurysm)
Causes
• High Blood Pressure, Smoking, High Cholesterol levels,
Obesity, Diabetes, Alcohol, Genetics, Atherosclerosis,
Oral contraceptives
Sign and symptoms (depend on area of brain affected)
• Headache, numbness, tingling, visual disturbance,
hemiparesis, hemiplegia, dysphasia/aphasia, dysphagia
Treatment
• Medications – Thrombolytic therapy – dissolves clots
• Craniotomy to tie off aneurysm
TIA
Transient Ischaemic Attack (TIA)
Temporary reduction in blood flow to an area of the brain
May be a warning a future stroke may be imminent.
Symptoms similar to a stroke
Parkinson’s
Loss of dopamine (neuro-transmitter) producing cells of brain
Dopamine influences initiation, modulation and completion of
movement
Occurs mainly in the elderly but can manifest in the 40’s & 50’s
S &S
Bradykinesia
(Slowing down of movement - especially automatic)
Hand Tremor (pill rolling of fingers)
Stooped posture and shuffling gait (short running steps)
Mask-like expression/Infrequent blinking
Muscle rigidity – lack of coordination/jerky movements, difficulty
with initiation of movement
Treatment
• Dopamine replacement medications
multiple sclerosis
A chronic disease caused by the progressive demyelination of the white matter of the brain and spinal cord. These sporadic patches of demyelination in the CNS cause interruption or blockage of nerve impulse
Characterised by periods of exacerbation followed by periods of remission, the remission periods may last several years (partial healing can occur)
The cause is unknown but it may be autoimmune and probably has a genetic component
Onset usually between 15 and 50 years of age and mainly women.
Signs and Symptoms • Spasticity/ tremors • Fatigue (early sign, often cause of diagnosis) • Bladder and bowel problems (later) • Sensory symptoms/visual changes • Motor dysfunction: balance, muscle coordination, muscle weakness • Minor cognitive and motor functions • Vertigo
Treatment
• Medications – Immunotherapy, Corticosteroids
