Kill Myslef Flashcards
(68 cards)
What do the exocrine glands do and what are the parts
Secrete substances through ducts or tubes onto a body surface or into a cavity
Salivary glands
Prostate gland
Milk glands
What are endocrine hormones and how are they classified?
chemicals secreted by endocrine glands directly into the blood
classified according to their activation site
What do non-target hormones affect?
affect many cells throughout the body; eg. insulin, epinephrine, GH, somatotropin.
What do target hormones affect?
affect specific cells or target tissues; eg. parathyroid hormone, gastrin
What do endocrine hormones not affect?
Do not affect all cells - only cells with receptors for that target cell.
2 types of hormones
Steroid Hormones & Protein Hormones
Steroid Hormones: what are they made of? What are (not) soluble in? Examples?
made from cholesterol - complex rings of C, H, O
Not soluble in water, but ARE soluble in fat (can dissolve across cell membranes)
eg. Sex hormones, cortisol (stimulates conversion of aas to glucose by the liver).
Steroid hormones: what do they diffuse from? What do they combine with and where?
Diffuse from capillaries to target cell
Combine with receptors in cytoplasm
How do steroid hormones do protein synthesis?
- Hormone/receptor complex moves across membrane to nucleus
- Attaches to chromatin with complementary shape
promotes or blocks transcription of a specific gene - Activates a gene that will initiate protein synthesis
Protein hormones: what do they contain? What are the soluble in? Examples?
Contain chains of amino acids
soluble in water
eg. insulin and growth hormone
Protein Hormones: What do they combine with and where?
Combine with receptors on cell membrane
What do Protein hormones do in protein synthesis? What is cAMP?
- Activates production of adenylyl cyclase
- Causes cell to convert ATP to cAMP
cAMP is a messenger – activating enzymes in cytoplasm to carry out their normal functions
What is the pituitary gland? What does it do? What is it connected to?
The ‘master’ gland
Exercises control over endocrine glands
Connected to hypothalamus
What does posterior lobe do?
stores and releases hormones that have been made in the hypothalamus (i.e. ADH and oxytocin)
What does Anterior lobe do?
produces its own hormones
hypothalamus nerves regulate their release
Where is the pancreas located? What functions does it have? What does it secrete?
located in the folds of the duodenum
has both endocrine and exocrine functions
secretes several key digestive enzymes
What are Islets of Langerhans? What do they have?
Specialized tissues in which the endocrine functions of the pancreas occurs
Have alpha (α), beta (β) and delta (δ) cells – each one secretes a hormone
What is glucagon secreted by and when? What does it do?
secreted by α cells when blood glucose levels ↓
Stimulates liver to
release glucose stores (glycogen to glucose) to blood
Make glucose (gluconeogenesis)
Glucagon: trigger, target & effect
Trigger: low glucose, sympathetic nervous system
Target: liver (mostly), adipose, muscles
Effect: breaks glycogen down into glucose
What is insulin secreted by? What do the cells take up?
Secreted by β cells when blood glucose levels ↑
Antagonistic to glucagon
↑ the rate cells take up glucose (thus lowers blood glucose)
Insulin: trigger, target & effect
Trigger: high glucose, food intake, GI hormones
Target: liver, adipose, muscles
Effect: stores glucose in tissues (glycogen), converts aa’s to pr-
Flow chart for glucagon
Stimulus (low blood glucose) -> monitor sensor (chemoreceptors in hypothalamus) -> coordinating center (hypothalamus triggers pancreas to release glucagon to blood) -> regulators effector (liver - converts glycogen to glucose) -> response (increased blood glucose)
Flowchart for insulin
Stimulus (high blood glucose) -> monitor sensor (chemoreceptors in hypothalamus) -> coordinating center (hypothalamus triggers pancreas to release insulin to blood) -> regulators effector (body cells - permeable to glucose, liver & muscle - convert glucose to glycogen) -> response ( lower blood glucose)
What is somatostatin secreted by? What does it do?
secreted by δ cells
inhibits effects of glucagon and insulin and many other hormones such as GH, TSH and gastrin