chemical co-ordination

Main Function:

It releases hormones into the blood to signal other cells to behave in certain ways. It is a slow but widespread form of communication.

NERVOUS COORDINATION

CHEMICAL COORDINATION

INVOLVES STIMULI

INVOLVES HORMONES

Endocrine glands Release hormones into the bloodstream.

Hormones are chemicals released in one part of the body that travel through the bloodstream and affect the activities of cells in other parts of the body.

Consists of:

ENDOCRINE GLANDS

PITUITARY FSH, TSH,GH, LH, Prolactin

THYROID THYROXIN

PANCREAS

ADRENALIN, ALDOSTERONE

OVARIESOESTROGEN

& PROGESTERONE

TESTIS TESTOSTERONE

ADRENAL

INSULIN & GLUCAGON

HYPOTHALAMUS ADH

The hormonal glands and their functions

Pituitary gland secretes:1. Growth hormone(GH) which stimulates growth in the body2. Thyroid stimulating hormone(TSH) which stimulate the thyroid to secrete thyroxin3. Follicle stimulating hormone (FSH) which stimulates the formation of follicles in the ovary.4. Luteinising hormone (LH) bringing about ovulation, oestrogen production and corpus luteum development.5. Prolactin which stimulates the mammary glands to secrete milk.

HypothalamusSecretes anti-diuretic hormone (ADH) which stimulate the re-absorption of water from the tubules back into the blood

Thyroid glandSecretes thyroxin (Iodine is necessary in the production of thyroxin) Thyroxin controls metabolic rate, particularly cellular respiration in mitochondria

Pancreas secretes:1. Insulin which decrease blood sugar levels2. Glucagon which increase blood sugar levels

Ovaries secrete:1. Oestrogen Stimulates the female sex organs stimulate secondary sexual characteristics2. Progesterone: Prepare uterus to receive fertilised ovum.Maintains the uterus during pregnancyTestes

Secretes testosterone which stimulate the male sex organs stimulates secondary sexual characteristics

Adrenal glands which secrete:1. Adrenalin which prepares the body for a crisis by increasing the:Heart rateBreathingGlucose levels in the bloodTone of the skeletal muscles2. Aldosterone which prepares the re-absorption of Na+ from the loop of Henlé.

Pituitary glandHypophysis (Pituitary gland)•also known as the master gland•situated in the small bony cavity on the floor of the skull, below the hypothalamus•has two lobes viz., the anterior lobe and the posterior lobe•the anterior lobe of the pituitary gland

Thyroid GlandFunction: plays a major role in regulation the

body’s metabolism.

Disorders: If the Thyroid Gland produces to much Thyroxin, it can cause a condition known as Hyperthyroidism. If to little thyroxin produces it is called Hypothyroidism.

NEGATAIVE FEEDBACK

The pancreas and Diabetes

Cause of diabetes: the pancreas makes little or no insulin

DIABETES

Islets of Langerhans•Small patches of special cells found in the pancreas•Secretes the hormones insulin and glucagonsInsulin •decreases the blood glucose level by stimulating the liver and muscle cells to absorb more glucose from the blood•promotes the conversion of glucose into glycogen and fat by the liver•deficiency of insulin results in diabetes mellitusGlucagon•increases the blood glucose level by encouraging the conversion of glycogen to glucose (energy needed in emergency situations)

Week circulation of blood to the legs and feet often causes limbsto be amputated.

Diabetes affects the circulatory system of the retina. The arteries in the retina become weakened and leak, forming small forming small, dot-like haemorrhages. These leaking vessels often lead to swelling or edema in the retina and decreased vision. In a later stage circulation problems cause areas of the retina to become oxygen deprived and new, fragile vessels develop as the circulatory system attempts to maintain adequate oxygen levels. These vessels haemorrhage (weaken) easily and blood may leak into the retina causing decreased vision

Prevention of diabetes1. Eat healthy, balanced meals

A should be followed to keep the glucose levels constant

Prevention of diabetes:2. Control the glucose levels. Normal glucose levels in the blood of a human should be between 3.5 – 5.5 mmol/l

Prevention of diabetes:3. Exercise regularly and keep the weight down (especially around the belly)

Study the following poster and discuss things which a diabetic should do and things which they should avoid

If diabetes is not managed well it may also cause kidney problems

GROWTH DISORDERSUNER PROCTION OF GH IN CHILDHOOD RESULT IN DWARFISM

OVER SECRETION OF GH IN CHILDHOOD RESULT IN GIANTISM

OVER SECRETION IN ADULTHOOD – ACROMEGALY (The bones become thicker, this is normally caused by a tumor of the pituitary gland)

Acromegaly – it causes enlarged feet and hands

THYROID GLAND

Thyroid GlandThyroid Gland•consists of two lobes, one on each side of the trachea, just below the larynx•secretes the hormone thyroxin

Functions of Thyroxin•maintains general metabolism at an optimum rate•essential for normal growth and functioning of the heart and nervous system •Iodine is essential for the production of thyroxin. A deficiency of iodine in the diet causes swelling of the thyroid gland (condition is called goitre)

THYROID GLAND

SECRETES THYROXIN

CONTROLLED BY

TSH

FUNCTIONS

Controls

1. metabolic rate of cells

2. how fast the heart beats & the force

with which it beats

3. Growth of cells & body tissue( eg bone % teeth

4. sexual development nerve reactivity

5 Mental development

Which is rich in Iodine

THYROID DISORDERSThyroxin regulates the body’s metabolic rate. Iodine is necessary in the production of thyroxin. A lack of iodine in the diet leads to an enlarged thyroid gland. This is known as

goitre.

Negative feedback

Hypothyroidism(under-secretion of thyroxin)Accumulation of body fluids in adults – hormone replacement tablets are prescribed

HYPERTHYROIDISM

Adrenal Gland•situated on top of each kidney•secrets the hormone adrenalin which prepares the body to cope with emergency, danger and stress in the following ways:•constricts blood vessels of the skin but dilates blood vessels to heart, muscles and brain (important organs during an emergency)•increases the heartbeat•promotes conversion of glycogen into glucose in the liver to be released into the blood•increase the rate and depth of breathing•increases skeletal muscle tonethe metabolic activity of the body cells increases to release more energy.

Cross section through the adrenal gland

Adrenal Gland Functions:

-The adrenal glands release Adrenaline in the body that helps prepare for and deal with stress.-Also regulates kidney function.

OvariesFunctions:

Pair of reproductive organs found in women that produce eggs.

Also secrete estrogen and progesterone, which control ovulation and menstruation.

TestesFunctions:

Pair of reproductive glands that produces sperm.

Also secrete Testosterone to give the body its masculine characteristics.

INFERTILITYCauses of infertilityNo FSH secreted, no eggs will be released and the female will

be infertileLow sperm count in males, sexually transmitted diseasesSymptoms Inability to have childrenPreventionReduce behaviour that may increase chances of contracting

STD’s Treatment of infertilityGynaecologist treats these women by giving them fertility

drugs that contain FSH and LH to stimulate their ovaries to produce ova. These drugs may cause many ova to be released resulting in multiple births.