1
Q
What major long-term processes are stimulated by hormones?
A
- Growth and development
- Metabolism
- Reproduction
- Energy balance
- Fluid and electrolyte balance
- Fight or flight response
2
Q
What are 3 of the main electrolytes and what is their function?
A
- Potassium = nerve impulse transmission
- Sodium = BP
- Calcium = bone growth
3
Q
How do exocrine glands work?
A
They release products at the body’s surface or into body cavities through ducts
- Examples: sweat/oil glands, liver, pancreas, salivary, prostate
4
Q
How do endocrine glands work?
A
They release products directly into the bloodstream
Do not have ducts
- Examples: pineal, pituitary, thyroid, hypothalamus, adrenal
5
Q
What are the 2 main types of exocrine glands?
A
- Simple duct structure
2. Compound duct structure (duct branches)
6
Q
What are the 2 structures of simple duct exocrine glands? Give 2 examples for each
A
- Tubular secretory structure
- Simple tubular (intestinal glands)
- Simple branched tubular (gastric glands) - Alveolar secretory structure
- Simple alveolar (paraurethral gland)
- Simple branched alveolar (sebaceous glands)
7
Q
What are the 2 structures of compound duct exocrine glands? Give examples for each
A
- Tubular secretory structure
- Compound tubular (duodenal glands) - Alveolar secretory structure
- Compound alveolar (mammary glands)
- Compound tubuloalveolar (salivary glands)
8
Q
Name 2 parts of the body that have secondary endocrine function
A
- Kidneys
2. Bone
9
Q
Describe the pituitary gland
A
- Located at the base of the brain
- 2 parts: anterior and posterior
- Hypothalamus controls the secretions of the pituitary gland
10
Q
Describe the posterior pituitary gland
A
- Formed of nerve cells surrounded by glial cells
- Hormones synthesised in the nerve cell bodies and stored in vesicles in the axon terminals
- Nerve impulses then trigger exocytosis of the vesicles to release the hormones
11
Q
What does the hypothalamus regulate?
A
- Temperature
- Thirst and hunger
- Sex drive
- Urine production
12
Q
Describe how the hypothalamus works
A
- Autonomic NS centre
- Controls the pituitary gland using neuro-secretory cells
- Produces relaxing hormones that control the anterior pituitary (AP) gland secretions
- Blood flows through the hypothalamus and then the AP gland, releasing and inhibiting hormones
13
Q
Where is the thyroid gland located?
A
At the front of the larynx and trachea at the level of the 5th, 6th and 7th cervical vertebrae
14
Q
Describe the thyroid gland
A
- Surrounded by a fibrous capsule
- Blood is supplied via the thyroid arteries
- There are 4 parathyroid glands
- Iodine is essential for the formation of thyroid hormones
15
Q
What is Calcitonin and how does it work?
A
- Hormone produced in the thyroid gland
- Lowers calcium levels by acting on bone cells to promote calcium storage and kidney tubules to inhibit calcium reabsorption
- Works with the parathyroid hormone to maintain calcium homeostasis
16
Q
How does the parathyroid hormone work?
A
Has the opposite effect of Calcitonin; stimulates bone destruction to increase calcium levels
17
Q
Describe the adrenal glands
A
- Make hormones that help the body prepare for and deal with stress
- Consist of a cortex and a medulla
18
Q
What does the adrenal cortex produce?
A
Corticosteroids which help maintain homeostasis
19
Q
What are the 3 groups of corticosteroids?
A
- Mineralocorticoids
- Glucocorticoids
- Sex hormones
20
Q
What does the adrenal medulla produce?
A
Epinephrine and Norepinephrine
21
Q
What is another name for epinephrine and what effect does it have?
A
- Adrenaline
- Reduces vasodilation
- Increases vascular permeability
22
Q
What is another name for norepinephrine and what effect does it have?
A
- Noradrenaline
- Vasoconstrictor
- Inotropic stimulator of the heart
- Dilator of coronary arteries
23
Q
What is unique about the pancreas and what are the 3 types of cells that it is made up of?
A
It has both exocrine and endocrine function
- alpha cells
- beta cells
- delta cells
24
Q
What are hormones?
A
- Chemical messengers produced in the body
- Generally pass directly into the bloodstream
- Influence other cells and tissues
25
What is a tropic hormone?
A hormone that has other endocrine glands as its target
26
What are the 2 main types of hormones?
1. Circulating hormone - diffuses into the blood to activate target cells far away
2. Local hormone- affect target cells close to their release site
27
What are the 2 main types of local hormone?
1. Autocrine - hormone-releasing cell is affected
| 2. Paracrine - hormone affects nearby cells only
28
Give 2 examples of local hormones
1. Histamine - synthesised and stored by mast cells in tissues and blood basophils
2. Prostaglandins - lipids in most tissue that act on neighbouring cells and are quickly metabolised
29
What are the 2 classifications of hormones?
1. Steroid (lipid) - Based Molecules - made from cholesterol, insoluble in water
2. Amino Acid - Based Molecules - water soluble
30
Give 2 examples of steroid-based molecules
1. Glucocorticoids (secretions from adrenal cortex)
| 2. Sex hormones (e.g. oestrogens and androgens)
31
What are amino acid-based molecules made from?
- Tryptophan and Tyrosine
- Peptides (e.g. ADH, oxytocin)
- Proteins (e.g. insulin)
- Amines (e.g. melatonin, thyroxine)
32
Describe what targets and receptors are for
- Hormones bind to specific target cells
- Cells have specific receptors for the hormone to bind to
- Receptors are made of glycoproteins and are located on the plasma membrane/ inside the cell
33
Describe the step-by-step process of steroid-based hormones acting on a cell
1. Hormones diffuse into the target cell where they bind with intracellular receptors in the nucleus
2. Hormone-receptor complex is formed
3. Hormone binds to the DNA
4. RNA produced (transcription and translation)
5. Newly formed protein affects target cell
This is known as Gene Activation
34
Describe the step-by-step process of amino acid-based hormones acting on a cell
Cannot diffuse into cells
1. Bind to receptors in the plasma membrane
2. The hormone is the 'first messenger'
3. Cycle Adenosine Monophosphate (cAMP) is the 'second messenger'
4. cAMP catalyses reactions which result in cellular change
35
What are the 3 stimuli that cause hormone release?
1. Hormonal
2. Neural
3. Humoral
36
Describe hormonal stimulation
- Stimulated by another hormone (stimulating/releasing hormone)
- Example - anterior pituitary secretes thyroid stimulating hormones which stimulates the thyroid to secrete thyroxin
37
Describe neural stimulation
- Stimulated by a nerve impulse
| - Example - sympathetic NS stimulates the secretion of norepinephrine and epinephrine by the adrenal medulla
38
Describe humoral stimulation
- Stimulated by levels of substances in the blood
- Example - blood calcium levels regulate parathyroid hormone levels and thyroid gland secretion of calcitonin
- Example - blood sugar levels regulate secretion of insulin by the pancreas
39
What are epinephrine and norepinephrine collectively known as?
Catecholamines
40
Describe the process of humoral stimulation in response to high blood glucose levels
1. High blood glucose level
2. Beta cells of pancreas stimulated to release insulin
3. Insulin acts on body cells to take up more glucose and liver to take up glucose and store it as glycogen
4. Blood glucose level declines to set point
41
Describe the process of humoral stimulation in response to high calcium levels
1. High calcium levels
2. Thyroid gland releases calcitonin
3. Calcitonin stimulates calcium salt deposit in bone
4. Calcium levels decline to set point
42
Describe the process of humoral stimulation in response to low blood glucose levels
1. Low blood glucose levels
2. Alpha cells of pancreas stimulated to release glucagon into the blood
3. Liver breaks down glycogen and releases glucose
4. Blood glucose levels increase to the set point
43
Describe the process of humoral stimulation in response to low calcium levels
1. Low calcium levels
2. Parathyroid glands release parathyroid hormone
3. Osteoclasts degrade bone matrix and release calcium into the blood
4. Calcium levels increase to set point
44
List 7 common effects of abnormal secretion of thyroid hormones
1. Increased basal metabolic rate
2. Weight loss, good appetite
3. Anxiety, physical restlessness, mental excitability
4. Hair loss
5. Tachycardia, palpitations, atrial fibrillation
6. Warm, sweaty skin, heat intolerance
7. Diarrhoea
45
What is Hypothyroidism?
Decreased T3 and T4 secretion
46
List 7 common effects of Hypothyroidism
1. Decreased basal metabolic rate
2. Weight gain, anorexia
3. Depression, psychosis, mental slowness, lethargy
4. Dry skin, brittle hair
5. Bradycardia
6. Dry, cold skin, prone to hypothermia
7. Constipation
47
Name 6 pancreatic hormones
1. Glucagon
2. Insulin
3. Somatostatin
4. Pancreatic polypeptide
5. Gastrin
6. Pancreatic juice
48
Describe glucagon
- Produced by alpha-islet cells
- Breaks down glycogen in the liver and muscles
- Increases glucose levels in the blood
49
Describe insulin
- Produced by beta-islet cells
- Increases membrane permeability for glucose
- Excessive glucose oxidation in tissues
- Lowering the glucose level in the blood
- Synthesis of glycogen in the liver and muscles
50
Describe somatostatin
- Produced in beta-islet cells
| - Inhibit release of gastrointestinal hormones
51
Describe pancreatic polypeptide (PP)
- Produced by PP cells
- Self-regulate the pancreas secretion activities
- Effect the hepatic glycogen levels
52
Describe gastrin
Aids digestion
53
Describe pancreatic juice
Contains enzymes for digestion
54
What are the ideal parameters for blood glucose?
```
Adult = 4-7mmol/l
Child = 4-8mmol/l
Elderly = 6-9mmol/l
```
55
What does post prandial mean and how does it affect blood glucose?
- After meals
| - Increases levels by up to 2mmol/l
56
Describe type 1 diabetes
- Severe deficiency or absence of insulin secretion
- Destruction of beta cells
- Daily insulin is required as treatment
57
Describe type 2 diabetes
- Insulin secretion may be low or above normal
- Insulin resistance can occur
- Treated with diet, exercise and/or drugs and sometimes insulin
58
What are the main causes of type 2 diabetes?
- Obesity
- Increasing age
- Inactivity
- Unhealthy lifestyle
59
What do releasing and inhibiting hormones do?
- Released by the hypothalamus
- Travel in connecting veins to the anterior pituitary
- Control the release of hormones
60
How are oxytocin and ADH moved and stored?
Transported along neuro-secretory cells to the posterior pituitary gland for storage until nerve impulses from the hypothalamus stimulate their release
61
What are the 3 main hypothalamic hormones?
- Releasing and inhibiting hormones
- Oxytocin
- ADH
62
Give 6 examples of hypothalamic hormones
1. Adrenocorticotrophic hormone (ACTH)
2. Growth hormone (GH)
3. Thyroid stimulating hormone (TSH)
4. Follicle stimulating hormone (FSH)
5. Luteinising hormone (LH)
6. Prolactin (PRL)
63
What is the function of Growth hormone?
Stimulates growth of all tissues in the body, including bone
64
What is the function of Prolactin?
Stimulates lactation in response to suckling
65
What is the function of Follicle-Stimulating hormone?
Stimulates growth of ovarian follicles and triggers production of oestrogen
66
What is the function of Luteinising hormone?
Triggers ovulation and development of the corpus luteum
67
What is the function of Thyrotrophic hormone?
Stimulates thyroid to produce thyroid hormone which regulates metabolic activity
68
What is the function of Adrenocorticotrophic hormone?
Regulates levels of the steroid hormone cortisol
Physical Health Sciences
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