 |
The Endocrine Glands and the Hormones they Produce |
 |
| Gland |
Situation |
Hormones
produced |
Action |
| Thyroid |
The
gland lies alongside the trachea at the end nearest the mouth |
Thyroid
hormone |
Controls
the activity of the body tissues. Deficiency
(hypothyroidism)results in poor growth in young animals. Older
animals, lacking in the hormone, become sluggish, overweight and have
poor hair growth. Excess amounts of the hormone cause
hyperactivity |
| Parathyroid |
Two
small glands alongside the thyroid |
Parathyroid
hormone |
Controls
the calcium stores in the body and is therefore important in the
development of the skeleton |
| Adrenal |
Two
glands near the kidneys |
Adrenaline-produced
by the centre of the gland (medulla) Corticosteroids - produced by the outer layer of the gland (cortex) |
Prepares
the animal for action and is excreted in quantity if the animal is
frightened, needs to fight or run away One group of these hormones controls the salt and the water content of the body. The other hormones produced by the adrenal cortex enhance the animals resistence to stress and infection. Excessive production of corticosteroids causes Cushings Syndrome. Addison's disease is caused when too little hormone is produced |
| Pancreas |
Lies
in the loop in the small intestine |
Insulin
and Glucagon |
These
hormones control the amount of glucose in the blood. Animals with
diabetes lack the hormone insulin or it is ineffective |
| Testes |
The
two testes are situated in the scrotal sac |
Testosterone |
Responsible
for the male characteristics of dogs, particularly aggression |
| Ovaries |
Contained
in the abdomen near the kidneys |
Oestrogen Progesterone |
Responsible
for the female characteristics of bitches. Stimulates the genital
tract and causes bleeding when the bitch is 'on heat'. Also
brings about development of the mammary glands Progesterone is responsible for preparing the uterus so that it can support the foetuses. It maintains pregnancy. It causes the mammary glands to develop so that they can eventually produce milk |
| Pituitary |
Situated
at the base of the brain. The gland is divided into two parts,
the anterior and the posterior |
Anterior part Thyrotropic hormone Corticotropic hormone Growth hormone Gonadotropins Follicle-stimulating hormone Luteinizing hormone Prolactin Posterior part Anti-diuretic hormone Oxytocin |
Controls the action of the thyroid Controls the action of the adrenal cortex Controls the animal's growth particularly up to puberty Promotes the ripening of eggs in the ovaries Causes ovulation Stimulates the mammary glands so that they are ready to produce milk Acts on the kidneys to prevent excessive excretion of water Makes the pregnant uterus contract at whelping and stimulates the release of milk from the mammary glands |
source: Doglopaedia A complete guide to dog care J.M.Evans & Kay White
