Zoology Ctd:
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- Central Nervous System composed of _________ and ________
- brain and spinal cord
- Peripheral Nervous System composed of _________
- all structures lying outside of CNS
- A structural and functional unit of NS; capable of conducting nervous impulses
- Neuron
- Conduct sensory info from a peripheral body part to the CNS for intepretation
- Sensory Neurons
- Conduct info within the CNS
- Interneurons
- Conduct motor info from the CNS to a peripheral body part
- Motor neurons
- Reception of stimulus; short, multiple processes
- Dendrites
- Location of nucleus and most organelles
- Cell body
- Conducts action potential away from cell body; single long process; branching only at terminal end
- Axon
- Axon insulated by a wrapping of myelin formed by Schwann Cells in the PNS and obligodendrocytes in CNS; conduct impulses a faster rate
- Myelinated
- Bundles of Axons bound together
- Nerves
- Composed of axons of sensory neurons
- sensory nerves
- composed of axons of motor neurons
- motor nerves
- composed of axons of both sensory and motor neurons
- mixed nerves
- A rapidly moving change in electrical membrane potential of an axon
- Action Potential or nerve impulse
- has an all or none effect
- Action Potential
- Differ in charge distribution across the plasma membrane
- Resting Membrane Potential
- Negative with respect to the Extracellular fluid outside due primarily to large protins carrying negative charges; resting potential is usually 70 Millivolts with the inside of the membrane negative to the outside
- Inside Axon
- Positive with respect to the inside
- Outside Axon
- Rapid, brief reversal of the RMP; Na+ gates open and NA+ rush into cytoplasm of Axon; Interior now slightly + with respect to the exterior
- Depolarization
- Reestablishment of the RMP; K+ gates open and K+ rush out of the axon
- Repolarization
- Na+/K+ pump moves Na+ out of axon and K+ back inside
- Reestabliment of RMP
- Region where an Action Potential passes b/w neurons (typically b/w and axon and a dendrite?
- Synapse
- Neurons are seperated by a space called the ____________
- Synaptic Cleft
- Neurons conducting impulses to the cleft:
- Presynaptic Neurons
- Neurotransmitters within presynaptic cleft
- Acetylocholine
- Neurons conducting impulses away from the cleft:
- postsynaptic neurons
-
1. conducts impulses from all levels to brain.
2. center for spinal reflexes
3. reflex - Spinal Cord
- An automatic involuntary response to a stimulus
- Reflex
- Function: motor area controls voluntary muscle movements: sensory cortex is center of conscious perception of touch, pressure, vibration, pain, temerature and taste; association areas integrae and process sensory data
- Cerebrum
- Part of limbic system: integrates sensory info arriving at Thalamus, projects to cerebral frontal lobes
- Thalamus
- Controls autonomic fuctions; sets appetitive drives(thirst, hunger, sexual desire) and reproductive behavior; participates i emotional responses; secretes ADH, and hormones for anterior pituitary regulation
- Hypothalamus
- Involuntary coordination and control of outgoing movements for equilibrium, muscle tone, posture
- cerebellum
- Links cerebellum with other brain centers and with medulla and spinal cord; modifies ouput of repiratory centers in medulla
- Pons
- Regulats heart rate and force of contraction; vasomotor control; sets rate of repiration; relays info the cerebellum
- Medulla Oblongata
- Conducts sensory messages from PNS to CNS for interprataion
- Sensory (Affarent) Division
- Conducts motor messages from CNS to Skeletal muscle (voluntary musle)
- Somatic Nervous System
- Conducts Motor messages from CNS to cardiac and smooth muscle (involuntary muscle) and internal organs/glands.
- Autonomic Nervous System
- 2 types of Motor (efferent) division
- Somatic NS and Autonomic NS
- 2 types of Autonomic NS
- Parasympathetic NS; Sympathetic NS
- Regulates activites during nonstressful periods.Constricts pupil, promotes digestion, decrease heartbeat heartbeat rate, decrease ventilation rate
- Parasympathetic NS
- Fight or Flight response; predominates during stressful periods: dilates bronchioles and pupil of eye, increase heartbeat rate, increase ventilation rate, increase blood flow to skeletal muscle, inhibits digestion
- Sympathetic NS
- Different in ion distributin inside and outside of neuron. Higher concentration of Na outside of axon. Higher Concentration of K inside axon
- Ion distribution