Autonomic and Endocrine Systems Flashcards
PNS
- Cranial nerves
- spinal nerves
- ganglia
- peripheral nerves
CNS
- Brain
- Spinal cord
afferent neurons
sensory
towards the spinal cord
efferent neurons
motor
away from the spinal cord
somatic
voluntary - skeletal muscle
autonomic
involuntary
sympathetic or parasympathetic - Cardiac muscle, smooth muscle, and glands
synaptic transmission
- nerve impulse
- voltage gated Ca2+ channel
- synaptic vesicle fuses to presynaptic neuron
- neurotransmitter diffuses across cleft
- binds receptor on ligand-gated channels
- Na+ enters
alarm response
sympathetic
relaxation response
parasympathetic
constriction of bronchi
parasympathetic
contraction of pupil
parasympathetic
decreased salavation
sympathetic
decreased digestion
sympathetic (because its a long-term process we don’t need)
pupils dilate
sympathetic
sympathetic response associated with…
exercise, emotion, excitement
parasympathetic response associated with…
repletion, rest, relaxation
sensory input for autonomic nervous system
mainly interoceptors (internal sensing)
sensory input for somatic nervous system
special senses and somatic senses
control of output for autonomic
involuntary from limbic system, hypothalamus, brain stem and spinal cord
control of output for somatic
voluntary control from cerebral cortex
motor neuron pathway for autonomic
two-neuron pathway
motor neuron pathway for somatic
one-neuron pathway
neurotransmitters in autonomic
ACh and noraepinephrine
neurotransmitters in somatic
ACh
effectors of the autonomic nervous system
smooth muscle, cardiac muscle, glands
effectors of the somatic nervous system
skeletal muscle
noraepinephrine found where in the autonomic nervous system
postganglionic sympathetic fibres other than to sweat glands
Raynaud disease
excessive sympathetic stimulation following emotional stress or exposure to the cold, leading to chronic vasoconstriction, which causes fingers and toes to become ischemic (lack of blood) and appear white.
ACh found where in the autonomic nervous system
- preganglionic axons
- postganglionic parasympathetic
- postganglionic sympathetic to sweat glands
Hypothalamus controls…
- internal organs via autonomic nervous system and pituitary gland
- body temperature
Hypothalamus regulates…
- behavioural patterns, circardian rythyms and sleep/wake cycles
- eating and drinking behaviour
Endocrine hormones affect
distant target cells
paracrine hormones affect
nearby target cells
autocrine hormones affect
same target cell
Mechanism of action of lipid-soluble hormones
- lipid soluble hormone diffuses into cell
- activated receptor-hormone complex alters gene expression
- newly formed mRNA directs synthesis of specific proteins on ribosomes
- new protein alters cell’s activity
Mechanism of action of water-soluble hormones
- binding to receptor activates G protein which activates adenyl cyclase
- activated adenyl cyclase converts ATP to cAMP
- cAMP serves as a second messenger to activate protein kinases
- activated protein kinases phosphorylate other enzymes
- phosphorylated enzymes catalyse reactions that produce physiological responses
Action of CHOLERA
Cholera toxin binds to G protein and locks G protein in active state. This leads to high cAMP which pumps Cl- into the lumen of the intestines. Water flows out = CHRONIC DIARRHOEA
infundibulum
connects the pituitary gland to the hypothalamus
hormones of the hypothalamus
- 9 hormones
- releasing and inhibiting hormones to control pituitary
hormones of the pituitary
- 7 hormones
- controlling endocrine organs
pituitary and hypothalamus work together to…
regulate growth, development, metabolism, homeostasis
hypothalamic control of the pituitary gland
hypothalamic neurosecretory cells release hormones from axon termini - hypophyseal portal vein - secondary plexus - pituitary target cells
adrenal medulla (hormones, stimulated by, principal actions)
- Hormones: Epinephrine and norepinephrine
- Stimulated by: ACh from sympathetic pre-ganglionic neurons
- Principal actions: Enhance alarm response
adrenal cortex hormones
A) Mineralocorticoids
B) Glucocorticoids
stimulation and action of Mineralocorticoids
increased K+ and Angiotensin II in the blood stimulates release. Mineralocorticoids then act to increase blood Na+ and water and decrease K+ which results in an increased blood volume and pressure
stimulation and and action of glucocorticoids
stimulated by ACTH from pituitary which in turn is stimulated by CRH from the hypothalamus. glucocorticoids act to dampen inflammation and depress immune responses (resistance reaction to stress)
aldosterone
mineralocorticoid
cortisol
glucocorticoid
Negative feedback effects on pituitary gland (cortisol example)
- CRH released from the hypothalamus
- ACTH released from the anterior pituitary
- cortisol released from adrenal cortex
- elevated cortisol inhibits release of ACTH by anterior pituitary corticotrophs
- elevated cortisol inhibits release of CRH by hypothalamic neurosecretory cells
Actions of glucocorticoids (e.g. cortisol)
- Increased protein breakdown (mainly in muscle fibres)
- glucenogenesis
- lipolysis
- resistance to stress
- vasoconstriction
- anti-inflammatory (inhibit WBCs that participate in the inflammatory response)
- immune depression
2 stages of the stress response
- fight-or-flight response:
- sympathetic
- immediate
- adrenal medulla (norepineprine and epinephrine) - resistance reaction:
- long lasting
- adrenal cortex (cortisol)
How does long-term sympathetic affect th heart
heart working harder and capillaries constricted which leads to a greater risk of cardiac infarct (heart attack)
types of stress
- eustress (acute) - prepares us to meet a challenge, beneficial
- distress (chronic) - associated with undesirable events, potentially harmful.
links between neuroendocrine and immune system. ______ nerves and ______ (e.g. cortisol) are features of the _________ system which influence the ________ system. The ______ system uses _______ (______ hormones) as its influence back onto the ________ system.
links between neuroendocrine and immune system. autonomic nerves and Hormones (e.g. cortisol) are features of the neuroendocrine system which influence the immune system. The immune system uses cytokines (immune hormones) as its influence back onto the neuroendocrine system.
