Mod 5 Endocrine system 1 Flashcards
What is the endocrine system?
The endocrine system is one of 2 major control systems in the body, the nervous system regulates organ function via electrochemical impulses (fast), on the other hand, the endocrine system regulates organ function via hormones (slower response)
What are the endocrine organs?
- scattered
- ‘ductless’ gland with rich blood supply
- contain hormone-producing cells
What are hormones?
- chemical messengers
secreted into blood or lymph - travel throughout the body to regulate other organs
- bind to specific receptors (lock and key) to initiate the response (needs to recognize the protein)
- effects last longer than the NS
Hormones?
Long-distance chemical signals travel in the blood or lymph and exert effects throughout the body.
Autocrine?
Short distance chemical signals exert effects on the same cells that secrete them, prostaglandins released by smooth muscle cells cause those cells to contract
Paracrine?
Paracrine are short distance chemical signals that exert effects on other cells that secrete them but with the same tissue i.e. somatostatin released by a different pancreatic cell
What do hormones regulate?
- growth and development
- electrolyte, water, and nutrient homeostasis
- cellular metabolism and energy production
- body defenses
- reproduction
Cellular level?
- Plasma membrane permeability or membrane potential/both by opening/closing ion channels
- synthesis of enzymes and other proteins within the cell
- activate and deactivate enzymes
- secretory activity
- mitosis
How does the chemical structure impact its effects?
the hormone’s chemical structure determines it’s solubility in water, it affects hormones transport before degradation and receptor interactions, either amino acid-based or steroid-based
What are different processes that occur in the NS and the endocrine system (COMP)
Nervous system:
- Rapid
- short-duration response
- acts via AP and neurotransmitters
- specific locations determined by axon pathways
Endocrine:
- slow
- long-duration responses
- diffuse locations (anywhere blood reaches)
What are the amino acid-based hormones?
Most hormones are in this group, with varying molecule size, amino acid derivatives, peptides proteins are water-soluble, they can’t cross the membrane
What are the steroid-based hormones?
They are synthesised from cholesterol includes adrenocortical and gonadal hormones, lipid-soluble, and can cross the plasma membrane.
How do hormones exert their effects? 1
- must have specific receptor (target cell)
- hormones increase/decrease preprogrammed cellular processes, regulate activity and not informational molecules
Can the same hormones have different effects on different target cells?
Yes, the same hormones have different effects on different target cells
i.e. adrenaline (contracts muscle but also dilates the bronchial in the lungs)
the degree of target cell activation depends on 3 factors, what are they?
1) blood levels of the hormones
2) the number of receptors for that hormone
3) the strength (affinity) binding
Can hormones have influence over other hormone receptors?
yes, hormones have influence over other hormone receptors e.g progesterone decreases estrogen receptors in the uterus, and estrogen increases progesterone receptors