Endocrine System Flashcards
What is a hormone?
Molecules that are released by endocrine glands directly onto the blood, act as messengers, carrying a signal from the endocrine gland to a specific target organ or tissue
How does endocrine system transport its signals?
Blood circulation system is used, transports materials all over the body
What is an endocrine gland?
A gland that secretes hormones directly into the blood, gave no ducts
What is an exocrine gland?
A gland that secretes molecules into a duct that carries the molecules to where they are used
How does is a hormone signal targeted?
Cells receive hormone signal must possess specific complimentary receptor on plasma membrane, hormone binds to receptor hormone only affects these cells, target cells
What is a target cell?
Those that poses a specific receptor on their cell surface membrane. Shape is complimentary to shape if hormone molecule
What are the two types of hormones?
Protein and peptide hormones and derivatives of amino acids
Steroid hormones
How do different types of hormone behave?
Proteins are not soluble so cannot enter cell, steroids however can pass into cell and have direct effect on DNA in the nucleus
What is adrenaline?
An amino acid derivative, causes fight or flight response, unable to enter cell,
How can adrenaline hormone have an effect on a cell?
Adrenaline receptor on outside of cell is associated with enzyme in the inner surface of the cell surface membrane, adenyl cyclase. When adrenaline binds to receptor as the first messenger, this activates enzyme adenyl cyclase, which converts ATP to cyclic AMP (cAMP), which is the second messenger inside the cell, that can then cause effect inside the cell by activating enzyme action
What is the first messenger?
The hormone that transmits a signal around the body
What is the second messenger?
cAMP which transmits a second signal inside the cell
Where are the adrenal gland found?
Found lying to the anterior or the kidneys m, one on each side, each gland can be divided into medulla and cortex region
Where are glands on the endocrine system found?
Pituitary gland in the brain Thymus Thyroid gland Adrenal glands Pancreas Ovaries
Where is the adrenal medulla found and what are its functions?
Found in the centre of the gland, manufacture and release adrenaline in response to stress such as pain or shock
What are the effects of adrenaline?
Relax smooth muscle in bronchioles, and increased breathing rate to ensure blood is fully oxygenated
Increase heart rate and stroke volume, increases cardiac output, faster and increased delivery
Constricting blood flow to digestive system, leaves more oxygen/glucose for muscle action
Raise blood pressure
Dilation of pupils
Conversion of glycogen to glucose
Body hairs erect
What is the role of the adrenal vortex?
Uses cholesterol to produce certain steroid hormones m, such as mineralocorticods that help control concentrations of sodium and potassium in the blood
Glucocorticoids that help contribute metabolism of carbohydrates and proteins in the liver
Why must target cells have a specific receptor?
Specific receptor for protein to bind, enables hormone to activate process inside the cell, complimentary so hormone only effects target cells
What is the pancreas?
Small organ below stomach? Has both endocrine and exocrine functions as it secretes both enzymes into pancreatic duct and hormones into the blood
What is the exocrine function of the pancreas?
Cells manufacture and release digestive enzymes into the ting tubules that surround the cells, tubules join to make the is pancreatic duct which carries fluid containing the enzymes into the first part of the small intestine
What enzymes are found in the pancreatic juice?
Amylase, a carbohydrase
Trypsinogen, an inactive protease
Lipase
Sodium hydrogencarbonate which make it alkaline to neutralise contents in small intestine from acid environment of the stomach
What is the endocrine function of the pancreas?
Islets of Langerhans contain alpha cells which manufacture hormone glucagon and beta cells which manufacture hormone insulin. Well supplied with blood capillaries and hormones are secretes directly into the blood
What are the Janet’s of Langerhans?
Small patches of tissue in the pancreas that have endocrine function
What is insulin?
Hormone released by beta cells that cause blood glucose level to fall