Human Physio
Terms
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- Interneurons
- -99% of all neurons -lie w/in CNS
- Afferent neuron
- -have sensory receptors -axon terminal in CNS -SENDS info from body to CNS
- Efferent neurons
- -RECIEVES info from CNS to body (effector organs) -cell body in CNS -axon terminal at effector organs
- Brainstem
- -critical connection link b/w brain and spinal cord -reception and integration of spinal cord input; activates and arosal of cerebral cortex -digestive, respiratory and cardiovascular control -Sleep/wake cycle -regulation of muscle reflexes: posture and equilibrium
- Cerebellum
- -Maintenance of balance -enhances muscle tone -coordination of voluntary muscle activity
- Hypothalamus
- -part of forebrain -Homeostasis & associated behaviors: ~Thirst & urine output ~food intake ~body temp ~uterine contraction and milk production (oxyctocin) -Link b/w nervous system and endocrine system ~smooth & cardiac muscle control ~exocrine gland control -Emotions & basic behavioral patterns
- Thalamus
- -part of forebrain -Relay station and filter for all input to cerebral cortex -crude awareness of sensation -some degree of consciousness -role in motor control
- cerebrum
- Basal nuclei & cerebral cortex
- Basal nuclei
- -Inhibition of muscle tone -coordination of slow sustained movement -supression of useless movement patterns
- Cerebral cortex
- -Sensory perception -voluntary control of movement -lagnuage -personality -consciousness & sophisticated mental events (thinking, memory, etc)
- Limbic system
- -EMOTIONS -Not a separate structure -interconnects: ~cerebral cortex ~basal nuclei ~thalamus ~hypothalamus
- Neural Basis of some human behaviors
- 1. Language and Speech 2. Emotions 3. Memory
- Language & Speech
- -Cerebral cortex
- Emotions
- -Limbic system -"attaches feeling to basic survival-related programs" of brainstem (feeding, aggression and sexuality) -birth: bond to caretaker, recognize and interact -Responses can be Autonomic, motor, hormonal -triggered by sensory input or memories -some emotions seem to associate w/ certain parts of brain
- Memory
- 1. Short term -relies on rapid changes in strength of existing nerve connections -frontal lobe 2. Long term -req's new connections among neurons -limbic system
- Normal capillary
- pores in walls for easy passage of materials
- Brain capillaries
- has tight junctions which block passageway from materials
- Glial Cells
- -90% of cell in CNS -50% of brain vol. -do NOT initiate or conduct nerve impulses -SUPPORT CNS neurons physically, metabolically & homeostatically
- Spinal Cord
- -31 pairs of nerves -carries and supports neurons b/w body to the brain
- The Blood Brain barrier: Hypothalamus
- Part is not subject to B-B barrier -able to monitor blood for hormones, etc.
- Blood Brain barrier: what does it do?
- It shields the brain from harmful blood changes
- Blood brain barrier: What can pass thru (diffuse thru) the Capillary membrane?
- small lipid soluble substances (CO2, alcohol, O2, steroid hormone)
- The brain can only make ATP from what?
- -from glucose -in presence of oxygen -can use ketones for part of energy
- The brain is dependent on what?
- -glucose and oxygen -4-5 min w/o Oxygen or 10-15 w/o glucose = brain damage/death
- Cross sections of the spinal cord include:
- Gray matter and white matter
- Gray Matter
- -Interneurons -Cell bodies of efferent neurons -axon terminals of afferent neurons *think ~ CNS classes
- White matter
- -myelinated axons organized into tracts (bundles of axons) b/w brain and spinal cord. -packaged phone lines -some ascend (to brain) and descend (from brain)
- The Reflex Arc: Reflexes include:
- -Spinal or Cranial -Somatic or Autonomic -Innate or Conditioned -Monosynaptic or Polysnaptic *see table 9.3 (pg 236)
- Withdrawal Reflex
- -complex -reflexes can be modified or overridden by CNS
- The reflex arc (steps 1-5)
- Stimulus --> 1. Sensory receptor --> 2. Afferent neuron --> 3. Integrating System (CNS) --> 4. Efferent neuron --> 5. Effector organs (muscle glands) --> response
- Parkinson's Disease
- -Destroys dopamine secreting cells in the brainstem -axon terminals from these cell arein basal nuclei -lack of dopamine = neurons in basical nuclei not getting messeages they need --> non-functional -Tremors -Rigidity -Difficulty moving -impairment of memory and thinking -1% over age 60 -cause: unknown
- What is the critical connecting link between the brain and the spinal cord?
- brain stem
- The part of the brain most involved in regulating homeostasis is
- The hypothalamus
- What controls the cardiovascular, respiratory and digestive systems?
- brain stem
- What supports the CNS physically and metabolically?
- Glial Cells
- What depends on tight junctions in brain capillaries?
- Blood-brain barrier
- What is made of 90% of the cells in the CNS?
- glial cells
- What shields the brain from changes in blood composition?
- Blood Brain Barrier
- The Reflex arc can be defined as:
- neural pathways for reflexes.
- Dopamine
- -A neurotransmitter w/ multiple functions in CNS -Basal nuclei: fine motor control -Frontal lobe: memory and learning -Reward seeking, pleasure, motivation -Addictions (drugs, gambling)