Endocrine system Flashcards
1
Q
What are the two types of endocrine glands and explain each?
A
Exocrine - Secrete into a duct (sweat, salivary, mucous)
Endocrine - secrete hormones into extracellular fluid.
2
Q
What are hormones?
A
- Chemical secreted by endocrine glands
- Transported in blood
- Can influence cells with matching receptor.
3
Q
What are the hormones actions?
A
- Activate genes
- Turn enzymes “on” or “off” by changing their shape
- Change rate of production of enzymes or proteins
4
Q
What do the hormones target?
A
- All cells
- Target cells
- Target organs
5
Q
Hypothalamus
A
- Connects the nervous and endocrine systems
- Functions are carried out through the pituitary gland
- Secretes RELEASING FACTORS and INHIBITING FACTORS that travel in the blood stream
- Produces oxytocin and ADH
6
Q
Pituitary gland
A
- Joined to hypothalamus by the infundibulum
- Anterior and posterior lobes
- APG is connected to hypothalamus by blood vessels and releases hormones under the influence of releasing factors
- PPG is connected to hypothalamus by specialised nerve fibres and stores hormones that are produced by the hypothalamus
7
Q
Anterior pituitary gland
A
Makes and secretes SIX hormones under the influence of the hypothalamus’s releasing factors (RF’s)
- Follicle-stimulating hormone (FSH) – development of ovum follicle and production and maturation of sperm
- Luteinising hormone (LH) – brings about ovulation and stimulates interstitial cells to secrete male sex hormones
- Growth hormone (GH) – stimulates growth, particularly the skeleton
- Thyroid-stimulating hormone (TSH) – stimulates production and secretion of thyroid hormones
- Adrenocorticotropic hormone (ACTH) – controls production and secretion of some adrenal cortex hormones
- Prolactin (PRL) –initiate and control milk production
8
Q
Posterior pituitary gland
A
Stores and releases TWO hormones into the bloodstream that are made by the hypothalamus
- Oxytocin (OT) – stimulates uterine contractions during childbirth and mammary gland contractions (milk “let-down”)
- Antidiuretic hormone (ADH) – causes kidneys to remove water from urine, returning it to the bloodstream
9
Q
Pineal
A
- It’s role is not well known
- Secretes melatonin – involved in sleep regulation
- Stimulated by darkness; inhibited by light
10
Q
Thyroid
A
- Releases thyroxine (T4) and triiodothyronine (T3)
- T4 controls body metabolism by regulating cellular reactions to release energy
- Causes an increase in body temperature
- Releases calcitonin - plays a role in regulating calcium and phosphate levels by reducing absorption in the kidneys
11
Q
Parathyroid
A
Secrete parathyroid hormone (parathormone) – increases calcium levels in the blood
- Calcium is released from bones into blood
- Calcium is absorbed in the intestines from digested food
- Calcium is reabsorbed into blood in kidneys
12
Q
Thymus
A
- Secretes a group of hormones called thymosins – influence the maturation of T-cells (immune system)
13
Q
Adrenal glands (adrenal medulla)
A
- Adrenalin – released in response to a threatening situation (fight or flight)
- Noradrenalin – similar to adrenalin, in particular it increases rate and force of heartbeat
14
Q
Adrenal glands (adrenal cortex)
A
- Cortisol – promotes normal metabolism, helping to withstand stress and repair damaged tissues
- Aldosterone – acts on kidney to reduce Na and increase K in urine
15
Q
Pancreas
A
- Is both an exocrine and endocrine gland
- Exocrine – secretes digestive juices into intestines
- Endocrine – islets of Langerhans secrete insulin and glucagon, both involved with blood sugar regulation
