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39 Cards in this Set
- Front
- Back
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What controls homeostasis of the body?
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The endocrine and nervous systems
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What does the nervous system do to control homeostasis?
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"1. Coordinates functions of the body by nervous impulses that pass to effectors and neurotransmitters that control the activity of the effectors
2. The nervous system acts quickly to alter the function of the tissues, but the effects do not last for a long time." |
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What does the endocrine system do to control homeostasis?
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1. Coordinates functions of the body by releasing hormones into the blood. The hormones alter cellular structure and function.
2. Thre endocrine system acts slower than the nervous system to affect change, but the effects are longer lasting |
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What are the 3 ways that hormones can affect target cells?
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1. Permissive effect requires 1 hormone to act before another?
2. Synergistic effect occurs when two hormones act together to produce a greater effect 3. Antagonistic effect is when one hormone opposes another hormone's action |
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What are the 2 types of hormones in terms of location?
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"1. Local hormones affect cells in the area of release
2. Circulating hormones affect cells distant to where they are" |
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What are the 2 types of local hormones?
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"1. Autocrine - affect the cell that produces it - eg. Interleukin II
2. Paracrine - Affects a cell closeby" |
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What is an example of a circulating hormone?
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Insulin
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What are the 4 different chemical structures of hormones?
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"1. Steroids
2. Eicosanoids 3. Amines 4. Peptides/proteins" |
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What is the structure of a steroid based hormone?
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4 ring structure similar to cholesterol from which it is derived
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Name 6 steroid based hormones
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"1. Aldosterone
2. Cortisol 3. Calcitriol (Vit D3) 4. Progesterone 5. Testosterone 6. Oestradiol" |
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What are the functions of hormones?
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"1. alter the rate of metabolism and ATP production
2. alter the rate of protein synthesis 3. alter the chemical composition or volume of fluid 4. affect the state of contraction of cardiac and smooth muscle tissue 5.alter the functions of the immune system 6. control growth and development 7. maintain homeostasis against stressors 8. controls reproduction" |
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What is the name of the cells that respond to a given hormone?
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Target cells
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What are the main 2 types of receptors for hormones?
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"1. Integrral proteins - that pass through the membrane
2. Glycoproteins - located on the extracellular side of the membrane" |
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What determines if a hormone is recognised by a cell?
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It needs to have the corrent three dimensional fit relative to the hormone receptor
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How does a cell regulate the numbers of receptors on a cell?
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If there is an increased need for a specific hormone then the cell up regulates and send more receptors to the cell membrane
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What is down regulation?
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Reducing the no. Of receptors on a cell surface
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What is the process for up regulation?
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The cell makes endosomes which send increased no. Of receptor molecules
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What is the mechanism for down regulation?
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Involves reducing the no. Of hormone receptors in a cell via receptor mediated endocystosis?
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Where do aldosterone and cortisol get formed?
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Adrenal glands
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Where do oestrogen and testosterone get formed?
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The gonads
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Where does Calcitriol get formed?
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The kidneys
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How are eicosanoid steroids formed?
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Arachadonic acid is formed from phospholipids from damaged cell membrane. Eicosanoids are derived from Arachidonic acid.
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Name the 3 amino acids which can be converted into hormones?
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1. Tyrosine - Thyroid hormones & dopamine and adrenalin hormones
2. Tryptophan - serotonin & melatonin 3. Histidine - Histamine |
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Which is faster the Endocrine system or nervous system in affecting change?
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Nervous system
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Name the 3 characteristics of endocrine system?
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"1. Individual ductless glands
2. rich in cqapillaries 3. form & secrete hormones 4. Unique cytology" |
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Name the 7 endocrine glands of the body?
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"1. Pineal
2. Ovaries 3. Testes 4. Thyroid 5. Parathyroid 6. Adrenal 7. Pituitary" |
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Where is the pineal gland found?
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Posterior part of epithalamus
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What does the pineal gland do?
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Regulates circadian rhythm
Produces melatonin Inhibits the gonad's development |
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What do the ovaries do?
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"House the ova
Mature the ova Produce oestrogen Produce Progesterone" |
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What do the testes do?
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"Produce sperm
Produce testosterone" |
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Describe the physical features of the thyroid?
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2 lobes connected by an isthmus covering the 2nd to 4th tracheal rings
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What the internal areas of the thyroid?
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Cuboidal epilthelium (dimensions depending on functional state),
filled with colloid (gelatinous substance) which contains storage form of Thyroid hormone (thyroglobulin) |
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What is the circulating form of the thyroid hormone known as?
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T3 - Triiodothyronine
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What is the name of the hormone that comes from the anterior pituitary and stimulates thyroid hormone production?
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TSH - Thyroid stimulating hormone
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What does TSH act on to produce thyroid hormone?
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Thyroid follicales
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What happens when there is not enough Iodine in the diet to convert TSH?
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TSH keeps stimulating the follicles and the thyroid enlarges and forms goitres
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Why do people near the sea rarely have goitres?
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They eat lots of Iodine rich foods from the sea
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What is the purpose of the thyroid hormone?
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Regulates metabolic rate in all tissues, Helps develops healthy nervous systems
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What happens if you are a child or an adult and don't have enough thyroid hormone?
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Cretin (Child), Myxoedema (Adult), Decreased mental mental and physical activity
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