L23 Flashcards
explain the nervous vs endocrine system
- Work together
- Nervous
○ Release neurotransmitters
○ Bind to receptors on target cells
○ Fast + local - Endocrine
○ Release hormones
○ That circulate through blood + bind to receptors on target cells
Slow + All over body
- Nervous
explain exocrine vs endocrine glands
- Exocrine
○ Secret their products into ducts
○ None are hormones
○ E.g. Of exocrine glands
§ Sweat glands
§ Oil glands
§ Mucous glands
§ Digestive glands- Endocrine glands
○ Secrete hormones
○ Do not have ducts
○ Secret their hormones directly into the interstitial fluid that surrounds them
○ E.g. Of endocrine glands
Pituitary, thyroid, adrenal, pineal glands
- Endocrine glands
//explain the basis of endocrine system
- Endocrine gland, goes to hormones, binding with receptor of target cells, triggers
1. Permeability of channel by acting on pre-existing channel forming proteins
2. Acts through 2nd messenger system to alter activity of pre-existing proteins
3. Activate a specific gene to cause formation of new proteins - All of which leads to a physiological response
explain circulating vs local hormones
- Hormones travelling throughout body only affect target cells that possesses specific protein receptors
- Receptors continually synthesised + broken down
- receptors may be down regulated in the presence of high concs. Of hormone
- Receptors may be up-regulated in the presence of low conc. Of hormones
- Hormones don’t circulate + act on cells close to where they are released called local hormones (paracrine hormones)
- Hormones that act on the cell that secretes them are called autocrine hormones
what are the 3 classes of hormones
amines, peptides, steroids
explains amines
○ Made by modifying amino acids
○ Called amines (because they retain amino group)
§ Thyroid hormones are called tyrosine
§ Histamine made histidine
Serotonin + melatonin made form tryptophan
explain peptides
○ Hormones that are amino acid polymers
§ E.g. ADH (anti-diuretic hormone), oxytocin, insulin
○ Protein hormones with carbs attached = glycoprotein
E.g. Thyroid stimulating hormones
explain steroids
○ Made from cholesterol
Each steroid hormone is unique due to presence of different chemical groups attached at various sites on the 4 rings at the core of its structure
explain lipophilic hormones
- Are lipid soluble
- Bind to receptors WITHIN target cells (because lipid soluble can easily fo through lipid membrane, so receptors found within)
- Slow acting
E.g. Thyroid hormone
explain hydrophilic hormones
- Water soluble
- Bind to receptor on surface
- Use 2nd messenger communication linked to protein phosphorylation
- Fast acting
E.g. ADH
explain hormones, and possible results
- Response to same hormone may vary depending on hormone itself + target cell
- Response may be to
○ Synthesis of new molecules
○ Change permeability of the cell membrane
○ Stimulate transport of a substance in/out of a cell
○ Alter rate of metabolic action
Contraction of smooth/cardiac muscle
- Response may be to
what are target cell responses to hormones based on
○ Hormone conc. In the blood
○ No. Of hormone receptor son the target cell
Permissive, synergistic + antagonistic effects
what is synergism
Strength by combination
explain permissiveness
- 1 hormone cannot work unless 2nd present
E.g. Thyroid + reproductive hormones
explain antagonism
- 2 hormones work against each other
E.g. Insulin + glucagon
