2 - APP - Unit 3.2 - The Endocrine System Flashcards
Gland
Any tissue or organ that produces a secretion
2 types:
- Endocrine gland
- Exocrine gland
Gland - Endocrine
Organized group of tissues which uses materials from the blood or lymph to make new compounds called hormones
AKA ductless glands or glands of internal secretion (secretion are released directly in bloodstream as blood circulate through the gland)
Secretion are transported to all body areas where they have special influence on cells, tissues & organs
Gland - Exocrine
Secretion from the gland must go through a duct (tube) that carries the secretion to a body surface of organ
Expl:
- sudoriferous glands - sweat
- sebaceous glands - oil
- salivary glands
- lacrimal glands - tears
- liver
- pancreas - performs as an exocrine gland (produces pancreatic juices going through a duct into small intestines) & endocrine gland (secretes hormone insulin directly into bloodstream)
Endocrine system
Secrete hormones or chemical messengers which coordinate and direct the activities of target cells and target organs
Majors glands
- Pituitary
- Thyroid
- Parathyroid
- Adrenals
- Gonads
- Pancreas
Each gland has specific function
Any disturbance cause changes in the appearance or functioning of the body
Hormonal control - Secretion of hormones
Operates on a negative feedback system or under the control of the nervous system
Hormonal control - Secretion of hormones - Negative feedback
Occurs when there is a drop in the level of a hormone, that triggers a chain reaction of responses to increase amount of hormone in the blood
Hormonal control - Secretion of hormones - Nervous system
Controls the glands which are stimulated by nervous stimuli, as in the adrenal medulla where the gland is stimulated by the sympathetic nervous system
Expl: when frightened, adrenal medulla secretes adrenalin
Glands of body - Pituitary Gland
A tiny structure located at the base of the brain.
Known as “master gland” because of its major influence on the body’s activities.
Pituitary gland is connected to the hypothalamus by a stalk called infundibulum.
Divided into :
- Anterior pituitary
- Posterior lobe
Glands of body - Pituitary Gland - Hypothalamus
Considered as part of the nervous system
Neurons in hypothalamus produce 2 hormones, stored and secreted by posterior pituitary lobe:
- Vasopressin - converts to antidiuretic hormone (ADH) (makes you not go pee)
- Oxytocin - causes strong contractions of uterus
Glands of body - Pituitary Gland - Infundibulum
Stalk connecting Pituitary Gland and Hypothalamus
Glands of body - Pituitary Gland & Hypothalamus process
[Anterior pituitary lobe]
The hormones in the anterior pituitary are controlled by the releasing chemicals or factors produced by the hypothalamus in the brain. As pituitary are needed by the body, hypothalamus releases specific releasing factor for each hormone.
[Posterior pituitary lobe]
Consists primarily of nerve fibers & neuroglial cells that support the nerve fibers.
Hypothalamus produces Vasopressin & Oxytocin that are stored in posterior lobe and are released into the bloodstream in response to nerve impulses from the hypothalamus
Glands of body - Hormones of the pituitary gland
- Growth hormone (GH) - somatotropin
Promotes growth and development. Help fat to be used for energy, saves glucose & helps maintain blood sugar levels - Prolactin hormone (PRL)
Develops breast tissue and stimulates production of milk after childbirth (function in males unknown) - Thyroid-stimulating hormone (TSH)
Stimulates growth and secretion of thyroid gland - Adrenocorticotropic hormone (ACTH)
Stimulates growth and secretion of adrenal cortex - Follicle-stimulating hormone (FSH)
Stimulates growth of Graafian follicle and production of estrogen in females.
Stimulates production of sperm in male - Luteinizing hormone (LH)
Stimulates ovulation & formation of corpus luteum (which produces progesterone in females) - Interstitial cell-stimulating hormone (ICSH)
Necessary for production of testosterone by interstitial cells of testes in men
Glands of body - Pituitary Gland - Vasopressin
Produced by neurons in hypothalamus
Converts to antiduiretic hormone (ADH) in the bloodstream.
Maintains water balance by increasing absorption of water in kidneys.
Diuretic drugs inhibit ADH action, resulting in increase in urinary output & decrease in blood volume, so a decreasing blood pressure
Glands of body - Pituitary Gland - Oxytocin
Released during childbirth or breastfeeding - Causes strong contractions of uterus
Pitocin: synthetic form of oxytocin helps labor
Glands of body - Pituitary disorders - Hyper functioning
Often due to pituitary tumor
Hyper secretion of pituitary growth hormone.
2 conditions:
- Gigantism
- Acromegaly
Glands of body - Pituitary disorders - Hyper functioning - Gigantism
Too much growth hormone during preadolescence (child)
Overgrowth of the long bones leading to excessive body growth
“Child becomes a giant”
Most common treatment: drug therapy (inhibits GH) & radiation treatments
Glands of body - Pituitary disorders - Hyper functioning - cromegaly
Too much growth hormone during adulthood
Adults whose long bones have already matured: growth hormone attacks cartilaginous regions & bony joints.
Overdevelopment/abnormal enlargement of the bones of:
- the face - chin protrudes, lips, nose enlarge
- the hands & feet
Lethargy & severe headaches.
Most common treatment: drug therapy (inhibits GH) & radiation treatments
Glands of body - Pituitary disorders - Hypo functioning - Pituitary dwarfism
Hypo functioning during childhood.
Growth of the long bones is abnormally decreased by an inadequate production of growth hormone.
- Small size, but body normally proportioned & normal intelligence
- Physique remains juvenile & sexually immature
Treatment: early diagnosis & injection of human growth hormone. Treatment for 5 years or more.
Glands of body - Pituitary disorders - Diabetes insipidus
Drop of ADH
Causes excessive loss of water and electrolytes.
Symptom: polydypsia (excessive thirst) and polyuria (production of abnormally large volumes of dilute urine)
Diabetes
= To pass thru
3 P’s of diabetes
- Polyuria - Excessive urination
- Polydypsia - Excessive thirst
- Polyphagia - Excessive hunger
Glands of body - Thyroid & Parathyroid glands - 3 hormones
[Thyroxine (T4)]
Controls rate of metabolism, heat production & energy creation with the cells. Can speed up or slow down activities of the body.
[Triiodothyronine (T3)]
Same effect as T4
5 to 10 times more active than T4, but activity less prolonged
[Calcitonin]
Lowers calcium levels in blood and body fluids by decreasing rate of osteoclastic activity (bone resorption) and by increasing osteoblastic activity (calcium absorption by bones - builders).
Proper calcitonin secretion prevents hypercalcemia (harmful rise in blood calcium level)
Thyroid hormones contain iodine coming form diet.
Glands of body - Thyroid & Parathyroid glands - Thyroid-stimulating hormone (TSH)
Controls the production and secretion of the thyroid hormones from the thyroid gland
