exam #2 Flashcards
what is homeostasis?
any process by which an organism tends to maintain a constant stable environment
what are the different components of homeostasis control system?
variable, receptors, control center and effectors
variable: increase/decrease in physiological variable caused by internal or external change
receptors: detect change in the variable
control center: receive the information and determines whether action is required
effectors: produce compensatory change in the variable
nervous system
- conscious: somatic nervous system
- unconscious: autonomic nervous system
- sensory: senses stimuli (change) in the body’s internal and external environment
- integrative: interpret stimuli
- motor: responds to stimuli by initiating muscle contraction or glandular secretions
endocrine system
- uses hormones
- responses generally take longer to appear
positive and negative feedback loops
negative: the response cancel pr counteract the original stimulus
positive: the response increase the original stimulus
what division of the nervous system is responsible for a specific action?
nervous system = central nervous system (CNS) + peripheral nervous system (PNS)
CNS: brain + spinal cord
PNS: peripheral nerves
afferent and efferent division
afferent division: carries the information about external (ex: temperature) or internal (ex: hunger) changes to the CNS (perceive stimuli)
efferent division: carries information from the CNS to effectors organ (ex: muscles, glands) (take action)
what are the difference between the somatic and autonomic nervous system?
somatic nervous system: voluntary action. Nerve fibers of the motor neurons that supply the skeletal muscles.
autonomic nervous system: unvoluntary action. Nerve fibers that innervate smooth muscles, cardiac, muscles, and glands.
what are the difference between the sympathetic and parasympathetic nervous system?
sympathetic: emergency (“fight-or-flight”), stressful situations. Prepares the body for strenuous physical activity.
parasympathetic nervous system: quiet, relaxed situations. Promotes body maintenance activities (ex: digestion, emptying the bladder).
what are the two ways to classify neurons?
- by function
- by structure
afferent neurons
- functional neurons
- also called sensory neurons
- their cell body is located inside the PNS, adjacent to the spinal cord
- their dendrites are located in the sensory organs
- generate action potentials in response to a particular type of stimulus (ex: touch)
action potentials are initiated at the receptor of the peripheral axon in response to a stimulus and are propagated along the axon(s) toward the spinal cord
efferent neurons
- functional neurons
- also called motor neurons
- the cell body is inside the CNS, but most of the neuron is in the peripheral nervous system
- efferent axon travel out of the CNS to meet the muscle glands they innervate
- upper motor neurons start in the cerebral cortex and end in the spinal cord
- lower motor neurons start in the spinal cord and end in the muscles
interneurons
- functional neurons
- also called association neurons
- are entirely located in the central nervous system
- about 99% of neurons belong in this category
two main role:
1. connect the afferent and efferent neurons and help integrate peripheral information to peripheral responses.
2. interconnections between interneurons themselves are responsible for the abstract phenomena associated with the mind (ex: thoughts, emotions, memory, creativity, intellect, motivation, etc)
flaccid paralysis
- damaged to the lower motor neurons
- no movement
- no reflexes
- muscles limp and flaccid
spastic paralysis
- damaged to upper motor neurons
- no voluntary reflexes
- increased muscle tone
