Chapter 4: General Physiology Flashcards
Hindbrain
medulla (natural rhythms)
pons (general awareness/awakeness, simple sensory processes)
cerebellum (muscle coordination)
Midbrain
tectum (auditory)
tegmentum (eye/motor movements)
Forebrain
thalamus (higher input of sensory systems, integrated b/f entering cortex)
hypothalamus (regulator of motivation and emotion)
pituitary gland (send regulatory hormones to this gland which sends other hormones)
basal ganglia (motor control, muscle movement)
limbic system
cerebral cortex (less evolutionary conserved, higher processing of sensory)
Hypothalamus
Responsive to:
Light (photosensitive) –circadian rhythms
Olfactory stimuli (pheromones)
Steroids (reproductive steroids from gonad and adrenal gland)
Neural info (processing of info from CNS & PNS)
Input from autonomic NS
Various peptide hormones and other subs from blood (receiving and regulating)
Hypothalamus
Controls influences upon:
- Autonomic NS
- Hormones from pituitary gland
- Aspects of bodily homeostasis
- Hunger, thirst, sex, maternal behaviour, fear, rage, etc.
Pituitary Gland
Anterior vs Posterior
Hypothalamus controls what hormones this gland releases (via signals)
Anterior (towards front) –connected to hypothalamus thru neuro-secretions (chemical signalling)
Hypothalamus releases hormones into blood, sensed by anterior which releases another hormone
Posterior (back) –made up of nervous tissue, neuronal inputs from hypothalamus (electrical signalling)
Sympathetic NS: flight/fight response
Arousal and energy expenditure (catabolic)
Increase HR and respiratory rate
Increase BP
Inhibits digestion
Decrease blood flow to digestive tract and skin
Increase blood flow to muscle and lungs
Dilation of pupils (take in more light, info from enviro)
Causes epinephrine release from adrenal glands
Piloerection (or goosebumps-hair stand on end –makes us look bigger)
Spontaneous urination and defecation (more common in smaller mammals)
**Response very quick
Parasympathetic NS: rest and digest
Calming, relaxation, energy storage (anabolic)
Decrease HR and respiratory rate Promotes digestion Increased blood flow to digestive tract Stimulates salivary gland secretion Involved in sleep, sexual responses
**Fires slowly
Sympathetic NS Synapsing
Spinal cord: thoracic, lumber
Neuron meets a second neuron, synapse, and then goes to an organ
- 1st neuron=pre-synaptic, 2nd neuron=post-synaptic
Ganglia: group/cluster of nerve cells=sympathetic chain (all neurons leaving the spinal cord in these regions pass thru this chain)
- Some neurons will synapse IN in chain ganglia, other will go through it
o Presynaptic release ACh
o Postsynaptic release norepinephrine
Parasympathetic NS Synapsing
Spinal cord: cranial (nerves), sacral
Nerves leaving the spinal cord synapse again very close to the organs
o Presynaptic release ACh
o Postsynaptic release ACh
Medulla
adrenal gland
rapidly secretes catecholamines into bloodstream in response to systemic NS (epinephrine and norepinephrine)
in response to stress/fear
very quick
Cortex
adrenal gland
slowly secretes steroids (cortisol, DHEA) in response to chemical stimulation (especially ACTH from pituitary)
Hormone
substance released into (and travels thru) the bloodstream that communicates with receptors at some distant site(s)
Neurotransmitter
substance released into the synapse when a presynaptic neuron fires, picked up by a receptor on the dendritic membrane of the postsynaptic neuron, affecting the probability that the postsynaptic neuron will fire
(excitatory or inhibitory influences)
Neuromodulator
substance in brain that changes response of neuron to some other factor
