endocrine system

Question 1

summarise link between nervous system and endocrine system

Answer 1

• NS has ultimate control while the endocrine takes instructions.
• NS uses electrical impulses, while ES uses hormones as chemical messengers

Question 2

draw table comparing NS to ES

Answer 2

example:
endocrine
-uses blood stream to transport
-quite slow to transport hormones
-relies on good blood supply
-same hormones for same response
-once hormone is released, cant be recalled
-speed of action is affected by decreased blood supply f like heat
-receives instructions from NS
-need lots of hormone to produce a response
————-

nervous system
-uses electrical signals
electrical signals are fast
-each tissue is innervated so can deliver specific messages to precise locations
-allows second to second updating
-uses different neurotransmitters to produce a variety of responses from same nerves according to need
-consistent in speedy responses
-ultimate control- autonomic
-Nervous can single out target cells with one nerve impulse
-

Question 3

ANATOMY OF ENDOCRINE SYSTEM

• pineal gland
• pituitary gland
• thyroid
• thymus
• adrenal cortex?
• pancreas
• ovary
• testes

Answer 3

Pineal gland: located deep in centre of brain in epithalamus. Produces melatonin, which helps maintain circadian rhythm and regulate reproductive hormones.
-Pituitary gland: follows orders from hypothalamus in the brain. Found in the diencephalon and sits in the hollow of the base of the skull called the SELLA TURCICA or Turkish saddle.

The job is to secrete hormones that control the other glands and cause them to release their hormones.
-Thyroid: releases hormones that control metabolism- the way your body uses energy.
The thyroid’s hormones regulate vital body functions, including: breathing, heart rate, central and peripheral nervous systems, body weight and muscle strength.

• Thymus: A gland but its main function is within the immune system. It is an organ in the upper chest cavity that processes lymphocytes ,a type of white blood cell that fights infections in the body.
• Adrenal cortex: control fight or flight response. These glands mobilise the sympathetic nervous system which causes blood vessel constriction, increased heart rate and blood to be diverted away from non-essential organs to heart and skeletal muscles, blood glucose levels increase
• Pancreas: The pancreas plays an essential role in converting the food we eat into fuel for the body’s cells.

The pancreas has 2 main functions: an exocrine function that helps in digestion and an endocrine function that regulates blood sugar.
The islets of Langerhans in the pancreas have alpha and beta cells producing different hormones; Alpha cells make glucagon and Beta cells make insulin.

• Ovary: Oestrogen causes maturation of the reproductive organs and stimulates female secondary sex characteristics at puberty; female sex hormones, acting with progesterone, promotes breast development and cyclic changes in the uterine mucosa. Progesterone is partly responsible for preparing the uterus for the fertilised ovum.
• Testes: Responsible for virilisation and is necessary for normal sperm production.

Question 4

What’s the difference between the 2 main hormones the AC can produce?

Answer 4

Adrenaline (epinephrine) is a potent stimulator of metabolic activities, bronchial dilation and increased blood flow to skeletal muscles and to the heart. Noradrenaline (Norepinephrine) has greater influence on peripheral vasoconstriction and blood pressure.

Question 5

describe the physiology of the ES in terms of hormones

Answer 5

• Hormones: chemical messengers, usually proteins, which cause an action in a p[articular organ or group of target tissues. Each hormone has a specific function. Endocrine glands secrete their hormone directly into the blood as it passes through the gland.
• Endocrine glands are called ductless glands because unlike other glands like sweat, mammary or salivary glands, these don’t pour their product into a duct to take to a destination. Glands with ducts are exocrine glands.

Question 6

what are the 2 main roles of the pancreas?

role of alpha in making glucagon VS beta cells in making insulin/

Answer 6

• Organ found in abdomen. Has 2 main functions:
1) Exocrine function to help digestion
2) Endocrine function to regulate blood sugar.
-Alpha cells produce glucagon
Glucagon: extremely potent hyperglycaemic agent, one mol can cause the release of 100 mill glucose mol into the blood. The major target is the liver which causes the breakdown of glycogen to glucose (Glycogenolysis).
-Beta cells produce insulin
Insulin is a hypoglycaemic agent whose main effect is to lower blood glucose, but it also influences protein and fat metabolism. It enhances membrane transport of glucose in to most body cells, especially muscle and fat cells. It inhibits the breakdown of glycogen and inhibits the conversion of amino acids/fats to glucose ( BUT glucose can normally enter kidney, liver and brain without insulin in a healthy person).

Question 7

the pituitary gland is made up of what 2 glands?

Answer 7

• The pituitary gland is 2 glands. The anterior pituitary or adenohypophysis, grew up towards your throat as a foetus. The posterior P, or neurohypophysis, grew down from the base of your brain when you were older.

Question 8

what hormones are found in the Adenohypophysis?

Answer 8

1) Growth Hormone (GH): which controls most tissues growth and cell development aka Somatropin. Growth hormone has as much effect on muscle function than on bone growth. Important for good cardiovascular health in adults. Used as a treatment to improve muscle tone and therefore global development for some syndromic disorders especially Prader Willi.
2) Thyroid stimulating hormone (TSH): Targets Thyroid Gland causing Thyroxine (T3 AND T4) release.
3) Adrenocorticotropic hormone (ACTH): stimulates cortisol (hydrocortisone) release by adrenal cortex, stimulated by fever hypoglycaemia and other stressors inhibited by glucocorticoids (i.e hormones that increase blood glucose levels and aid the body in resisting long term stressors).
4) Prolactin : targets the breast and promotes milk production
5) Luteinising hormone (LH): within the ovaries and testes. Stimulates ovulation and progesterone production on the ovaries, and testosterone production in the testes.
6) Follicle-stimulating hormone (FSH): ovary in females. Follicle maturation and oestrogen production in females. Testis in males. Spermatogenesis in males.
7) melanocyte stimulating hormone (MSH): targets melanocytes, which causes proliferation in skin.

Question 9

what hormones does the Neurohypophysis produce? significance?

Answer 9

• The Neurohypophysis is the posterior pituitary gland and produces ADH and oxytocin.

1) ADH (Vasopressin): Makes kidney tubules less permeable and reduce urine production. This is released to conserve water in the body.
2) Oxytocin: control milk production and uterine contraction. Also called the love potion as you secrete oxytocin during g sexual intercourse and any intimate contact. Even a hug will cause low levels of oxytocin to be released- it creates feelings of attachment.