Autonomic and Endocrine Systems Flashcards
Somatic nervous system
Voluntary
Skeletal muscle
Autonomic nervous system
involuntary cardiac + smooth muscle + glands two-divisions: - sympathetic (fight/flight) - parasympathetic (rest/digest)
Sensory input: Autonomic
Interoceptors (internal sensing)
Sensory input: somatic
Special/somatic senses
Control of output: Autonomic
Involuntary:
- lymbic system
- hypothalamus
- brainstem
- spinal cord
Control of output: Somatic
Voluntary:
- Cerebral cortex
Effectors: Autonomic
Smooth and cardiac muscle + glands
Effectors: Somatic
Skeletal muscle
The neurotransmitter in the somatic nervous system
Acetylcholine
Neurotransmitters in the autonomic nervous system
Sympathetic division:
- Ach for sweat glands
- Norepinephrine for effector cells
Parasympathetic:
- Ach for effector cells
Raynaud disease
- Excessive sympathetic stimulation following emotional stress or exposure to the cold
- chronic vasoconstriction
- fingers and toes become ischemic (lack blood) and appear white
Hypothalamus: controls internal organs via
Autonomic nervous system
Pituitary gland
Hypothalamus: Regulates
- behaviour patterns
- circadian rhythm (sleep/wake cycles)
- body temperature
- eating and drinking
Endocrine hormones
Puts hormones into the bloodstream which travels to distant target cells
Paracrine hormones
Transfer hormones to nearby target cells
Autocrine hormones
Same target cell
Cholera
- Cholera toxins bind to G protein, locking it in an activated state
- High cAMP
- pumps chloride ions into intestines
- water follows out
- chronic diarrhea
Hypothalamus
9 hormones (releasing and inhibiting hormones to control pituitary)
Pituitary
7 hormones synthesized in anterior pituitary for regulation of homeostasis
Anterior pituitary
- releasing and inhibiting hormones from the hypothalamus
- hypophyseal portal system (vascular connection)
- GH, MSH, TSH, ACTH, FSH, LH, PRL
Posterior pituitary
- hypothalamic - hypophyseal tract (neural connection)
- oxytocin and ADH
- response directly to hypothalamic hormones
The adrenal medulla is stimulated by
Ach from preganglionic neurons
Hormones released from the adrenal medulla
Epinephrine (adrenaline) and norepinephrine
Principle actions of the adrenal medulla
Enhance sympathetic autonomic alarm response, works slowly so prolongs response
Adrenal cortex: what is hormone A?
mineralocorticoids
Adrenal cortex: what is hormone A stimulated by?
Increased K+ and angiotensin II in blood
Adrenal cortex: what is hormone A’s principle action?
mineralocorticoids increase Na+ and water and decrease K+ in blood
increases blood volume and pressure
Adrenal cortex: Hormone B
Glucocorticoids (cortisol)
Adrenal cortex: What stimulates hormone B?
Glucocorticoid stimulated by ACTH from the pituitary (CRH from hypothalamus affects pituitary to form ACTH)
Adrenal cortex: principle action of hormone B?
- Resistance to stress
- Control (dampen) inflammation
- Alter immune response
The 3 stages of alarm response
1) Alarm response
2) Extended alarm response
3) The resistance response
Alarm response
- Immediate burst
- Sympathetic activation
- Adrenal medulla
Extended alarm response
- mediated by the hormones epinephrine and norepinephrine secreted by the medulla of the adrenal gland
Resistance reaction
- Slower, longer-lasting
- mediated by the hormone cortisol, secreted by the adrenal cortex
What makes up the CNS
Brain
Spinal cord
What makes up the PNS
- Cranial nerves
- spinal nerves
- ganglia
- peripheral nerves
What are afferent nerves
Nerves which bring impulses from the PNS to the CNS (sensory neurons)
What are efferent nerves
Nerves which take impulses from the CNS to the PNS (motor neurons
What are the different types of motor neurons?
Somatic and autonomic
What are the steps of nerve impulse conduction
- Impulse arrives at presynaptic membrane, depolarizing and opening voltage-gated Ca2+ channels.
- Ca2+ encourages vesicles of neurotransmitters to bind to the presynaptic membrane and leave into the synaptic cleft via exocytosis
- Neurotransmitters bind to ligand-gated channels in the postsynaptic membrane, causing it to depolarize due to inflow of Na+, causing the conduction of the impulse
(All this happens within milliseconds)
What is involved in alarm response and what causes it?
Caused by the sympathetic branch of the ANS
- Increased HR & contractility
- Contraction of arrector pili muscles (hair stands on end) and increased secretion from sweat glands.
- Constriction of blood vessels in the skin to send more blood to muscles
- Dilation of pupils for greater visual acuity
- Decreased salivation
- Dilation of bronchi
Increased blood sugar to give more glucose to muscles
- Increased BP and H2O retention
- Decreased digestion
- Increased resp. rate to increase O2 in the blood.
What is involved with the relaxation response and what causes it
Caused by the parasympathetic branch of the ANS
- Decreased HR & contractility
- contraction of pupils
- increased salivation
- dilation of peripheral blood vessels
- constriction of bronchi
- increased digestion
What are sympathetic nerve responses associated with?
- Exercise
- Emotion
- Excitement
- Danger
Why is sympathetic innervation important?
It gives the body the opportunity to be active
What are the parasympathetic responses associated with?
- Repletion
- Rest
- Relaxation
Why is parasympathetic innervation important
It gives the body the opportunity to recuperate
Where does sensory input for the ANS come from?
Interoceptors detecting change in O2 levels, hunger, and blood pressure
some impulses from the somatic nervous system
Where does sensory input for the SNS come from?
Special senses and somatic senses
What controls ANS output?
Involuntary control by the: - limbic system - hypothalamus - brain stem - spinal cord to change the body's environment
What controls SNS output?
Voluntary cerebral cortex decisions - causes the body movements
What is the motor pathway type in ANS?
Two neuron pathways: post- and pre-ganglionic pathways
What is the motor pathway type in SNS?
One neurons pathway - just LMNs
How are parasympathetic and sympathetic used in tandem?
Both are always active but can be turned up and down like a dimmer.
When there are danger, sympathetic increases while parasympathetic decreases and vice versa
This is important as if they are constantly in use, bad outcomes may result.
What is a similarity between ANS and SNS neurons
Both start within the spinal cord
What are the differences between ANS and SNS neurons?
- ANS has two neurons: the pre- and post-ganglionic, of which only the pre-ganglionic are myelinated.
- The two synapses in the autonomic ganglion, using ACh
- The SNS only has a single mylinated neuron
Why is it important that the ANS synapses in the ganglia?
It allows a single signal from a pre-ganglionic neuron to be sent to multiple post-ganglionic neurons
What does a cholinergic neuron use as a neurotransmitter>
ACh
What does an adrenergic neuron use as a neurotransmitter
Ne
What does a muscarinic receptor accept as a neurotransmitter?
ACh
Autonomic tone
The balance between sympathetic and parasympathetic activity
Glucocorticoids
Class of hormones released by the adrenal cortex, such as cortisol which plays a part in the resistance reaction
cytokines
Hormones released by the immune system can alter the autonomic nervous activity
Eustress
Stress which is acute and beneficial
Distress
Stress is prolonged and can have detrimental effects
Infundibulum
Small stalk linking hypothalamus to the pituitary gland
Primary capillary plexus
Superior capillary bed on the pituitary gland
Hypophyseal portal veins
Veins linking primary capillary plexus to secondary capillary plexus
What is the name for a pre-ganglionic neuron?
cholinergic
what is the name for a postganglionic neuron
adrenergic
Where is the thyroid locates?
top of the trachea
what is the name of the receptors in a sweat gland
muscarinic receptors
What process is the thyroid largely involved with?
Growth
What are the types of lipid-soluble hormones?
Steroid hormones, thyroid hormones
What are the types of water-soluble hormones?
Catecholamines, peptides, and proteins
Which part of the pituitary has hypophyseal portal veins on it?
anterior pituitary
Where are modified post-ganglionic neurons which act as secretory cells found?
adrenal glands
What types of cells are found in the adrenal glands?
modified postganglionic neurons which act as secretory cells
What hormones are used in the medulla?
epinephrine and norepinephrine
What hormones are used in the adrenal cortex?
Mineralocorticoids (e.g. aldosterone) and glucocorticoids (e.g. cortisol)
How is the adrenal cortex stimulated to release glucocorticoids?
ACTH from the pituitary which in turn is stimulated by CRH (corticotropin-releasing hormone) from the hypothalamus
What is the principal action of the adrenal medulla?
Enhance sympathetic autonomic alarm response
what is the principal action of the adrenal cortex releasing mineralocorticoids
increase blood Na+ and decrease blood K+ to increase blood volume and pressure
what is the principal action of the adrenal cortex releasing glucocorticoids?
resistance reaction to stress dampens inflammation and depresses immune response
