Endocrine System 🎯 Flashcards
With respect to size and myelination of cell axons, the velocity of nerve impulse conduction is greatest in
large-diameter heavily myelinated fibers
Clinical application: Multiple sclerosis (MS) is a disease that causes the progressive destruction of myelin sheaths / demyelination of nerves in the CNS and PNS. Choose the correct grouping of symptoms commonly seen in patients with MS from the choices below.
Numbness/weakness, electric-shock sensations, tremor, vision loss
Nerves
coordinate our actions and bodily functions
The Alarm Response =10
Heart: Increase rate and contraction force
• Eyes: Dilate pupils
• Mouth: Decrease saliva
• Lungs: Dilate bronchi and breathe faster • Skin:
• Constrict peripheral blood vessels
• Contract arrector pili muscles
• Increase sweat secretion
• Gut: Decrease digestion
• Increase blood sugar
• Increase blood pressure and water retention
The Relaxation Response =6
- Heart: Decrease rate and contraction force
- Eyes: Contract pupils
- Mouth: Increase saliva
- Lungs: Constricti bronchi, breathe more slowly
- Skin: Dilate peripheral blood vessels
- Gut: Increase digestion
Sympathetic Division Associated with:
• Exercise • Emotion • Excitement (Alarm response)
Parasympathetic Division Associated with:
• Repletion • Rest • Relaxation (Relaxation response)
Control of involuntary
Hypothalamus, Brain stem, Spinal cord
Lambic system
Voluntary: Control of
Cerebral cortex
Effectors for involuntary movement
Smooth muscle,
Cardiac muscle, Glands
Somatic
Motor neuron pathway:
Neurotransmitters…
. One neuron pathway
. Acetylcholine
Autonomic
Motor neurone pathway
Neurotransmitters
.2 neurons pre and post ganglioc
Acetylcholine: Preganglionic axons Postganglionic axons: Parasympathetic Sympathetic to sweat glands Norepinephrine: Postganglionic axons Sympathetic to other than sweat glands
Raynaud Disease
White fingers
Excessive sympathetic stimulation following emotional stress or exposure to cold • Chronic vasoconstriction • Fingers and toes become ischemic (lack of blood) and appear white
Hypothalamus
Controls internal
organs via: = 2
Regulates =4
- Autonomic nervous system
- Pituitary gland
- Behaviour patterns
- Circadian rhythm (sleep /wake cycles)
- Body temperature
- Eating and drinking
Paracrine Hormones
Targets nearby cells
Autocrine Hormones
Targets its self
Endocrine Hormones
Travels though blood and or body tissue to distant target cells
Lipid-Soluble Hormones
4 steps ?
1: Lipid-soluble hormone diffuses into cell
2: Activated receptor- hormone complex alters gene expression
3: Newly-formed mRNA directs synthesis of specific proteins on ribosomes
4: New protein alters cell’s activity
Water-Soluble Hormones
6 steps
1: Binding to receptor activates G protein which activates adenyl cyclase
2: Activated adenyl cyclase converts ATP to cAMP
3: cAMP serves as second messenger to
activate protein kinases
4: Activated protein kinases phosphorylate other enzymes
5: Phosphorylated enzymes catalyse reactions that produce physiological responses
6: Phosphodiesterase inactivates cAMP
Inducibility
capable of being induced:
such as. a : formed by a cell in response to the presence of its substrate inducible enzymes. b : activated or undergoing expression only in the presence of a particular molecule an inducible promoter.
Effects of Cholera
Locks G protein in activated state
• Pumps chloride ions into intestines
• Water follows out
• High cAMP
= chronic diarrhoea
What are the really colourful parts on top of the hypothalamus
Hypothalamic nuclei
What connected the pituitary to the hypothalamus
Infundibulum
hypophyseal pituitary
portal veins
Portal system between the two
capillaries - portal vein - capillaries
Pituitary
7 hormones (controlling endocrine organs)
Hypothalamus
9 hormones
releasing and inhibiting hormones to control pituitary
Hypothalamic
neurosecretory cell
Releasing and inhibitory hormones released from axon
termini
Step 2 of the Hypothalamus-Pituitary Axis
Hormones travel through portal vein to secondary plexus then into pituitary target cells
Three layers of the Adrenal Gland
Capsule
Cortex
Medulla
The Adrenal Medulla is stimulated by
Acetylcholine from preganglionic neurons
Adrenal Medulla Hormones released:
Epinephrine (adrenaline) and norepinephrine
Adrenal Medulla Principal actions:
Enhance sympathetic autonomic
alarm response
The Stress Response First stage
Alarm (Fight-or-flight) response:
- Immediate burst
- Sympathetic autonomic activation
- Sustained through action of adrenal medulla
Adrenal Cortex
Hormones A:
Mineralocorticoids (e.g. aldosterone)
The Adrenal Cortex Stimulated by:
Hormone A
Increased K+ and angiotensin II in blood
The Adrenal Cortex Principal actions:
Hormone A
• Increase Na+ and water and decrease K+ in blood
=> Increase blood volume and pressure
The Adrenal Cortex Hormones B:
Glucocorticoids (e.g. cortisol)
Adrenal Cortex
Hormones B:
Stimulated by:
ACTH from pituitary (CRH from hypothalamus)
The Adrenal Cortex Hormones B:
Principal actions:
• Resistance reaction to stress • Control (dampen) inflammation • Alter immune responses
Resistance reaction:
• Slower, longer lasting • Associated with hypothalamus,
pituitary and adrenal cortex
Eustress (acute):
• Prepares us to meet certain challenges • Helpful, beneficial
Distress (chronic):
• Associated with
undesirable events • Potentially harmful
