Endocrine and Diabetes Flashcards
(150 cards)
1
Q
What are the 5 ways in which cells communicate?
A
- Neural communication
- Endocrine communication
- Paracrine communication
- Exocrine secretions
- Autocrine communications
2
Q
Describe neural communications between cells.
A
Neurotransmitter secreted at a synaptic junction.
3
Q
Describe endocrine communication between cells.
A
Hormones, secreted into the blood circulation, are carried to target tissues throughout the body.
4
Q
Describe paracrine communication between cells.
A
Products of secretion enter extracellular fluid to affect neighbouring cells.
5
Q
Describe exocrine secretions between cells.
A
The products of secretion are released into a body cavity.
6
Q
Give one example of an exocrine secretion.
A
Saliva into the mouth.
7
Q
Describe autocrine communication between cells.
A
Cells secrete chemical messengers that in some situations bind to receptors on the original cells.
8
Q
What discoveries did Arnold A. Berthold make in terms of behavioural endocrinology?
A
- The testes are transplantable organs.
- Transplanted tested can function.
- Nerves are not necessary, but a blood-borne product of the transplanted testes is important.
9
Q
How do endocrine glands exert control?
A
By releasing chemical hormone into the blood.
10
Q
Do endocrine glands have ducts?
A
No
11
Q
What parts of the body do the hormones released by endocrine glands affect?
A
Other endocrine glands or body systems.
12
Q
What processes do hormones control?
A
Homeostasis Reproduction Growth and development Metabolism Response to stress
13
Q
Describe how hormones are classified?
A
- Proteins
- Polypeptides (amino acid derivatives).
- Lipids (fatty acid derivatives or steroids).
14
Q
Describe the different categories of hormones available in the blood
A
- Constant level hormones
- Variable level hormones
- Cyclic level hormones
15
Q
What are the different classes of hormones?
A
- Amine hormones
- Peptide hormones
- Steroid hormones
16
Q
What are amine hormones derivatives of ?
A
Derivatives of the amino acid tyrosine.
17
Q
What is the other possible function of peptide hormones?
A
Used as neurotransmitters.
18
Q
Where are steroid hormones produced?
A
In the adrenal cortex and gonads.
19
Q
What are the different ways in which hormones can be transported in the blood?
A
- Water soluble hormones dissolve in the blood and travel via the plasma.
- Some hormones circulate in the blood, bound to plasma proteins.
- Free hormones diffuse across the capillary walls to encounter target cells.
20
Q
What are the two possible ways that hormones are removed from the blood?
A
They are either excreted by the kidneys or metabolised in the blood or target cells.
21
Q
Which cells act as targets for someones?
A
Cells that have receptors to bind the hormone.
22
Q
What can compensate for a low concentration of a hormone and what is this called?
A
An increase in the number of receptors. This is up-regulation.
23
Q
How does a high concentration of hormones affect receptors and what is this called?
A
The number of receptors for the hormone decreases.
This is down-regulation.
24
Q
How does the hormone-receptor relationship relate to antagonism?
A
A hormone can reduce the number of receptors available for a second hormone resulting in decreased effectiveness of the second hormone.
25
How does the hormone-receptoror relationship relate to permissiveness?
A hormone can induce an increase in the number of receptors for a second hormone, increasing the latter's effectiveness.
26
Where are receptors for the peptide hormones and catecholamines ?
Present on the extracellular surface of plasma membranes.
27
Where are receptors or steroid and thyroid hormones?
They are present on the intracellular surface of membranes.
28
Name some processes and factors that hormone receptor binding can affect.
- Ion channels
- Enzyme activity in part of a receptor.
- Activity of kinases.
- Gene proteins and second messengers
- Genes could also be activated or inhibited, causing a change in synthesis rate of proteins coded for by these genes.
29
What types of hormones does the hypothalamus secrete?
Hypophyiotropic hormones
30
What type of hormones does the pituitary secrete?
Anterior and posterior pituitary glands.
31
What type of glands are the hypothalamus and pituitary?
Endocrine.
32
How do secretions from the hypothalamus affect the pituitary?
They activate the pituitary to make secretions. The hypothalamus regulates the pituitary.
33
What is the main purpose of the anterior pituitary?
It controls the functions of numerous other endocrine glands.
34
Where is the anterior pituitary found?
In a bone cavity at the base of the skull.
35
What are the 5 endocrine cell types in the anterior pituitary ?
```
Gonadotroph
Lactotroph
Somatotroph
Corticotroph
Thyrotroph
```
36
Where is the pancreas located?
In the retroperitoneal space between the duodenum and spleen
37
Is the pancreas endocrine or exocrine?
Both
38
What are the exocrine functions of the pancreas?
Secrets key digestive enzymes such as amylase and lipase and neutralises the pH of the stomach acid entering the top of the duodenum.
39
What is the purpose of amylase?
Breaks down large sugars.
40
What is the purpose of lipase?
Breaks down fats.
41
What cells are in the endocrine section of the pancreas?
Alpha cells
Beta cells
Delta cells
42
Describe the purpose of the endocrine cells of the pancreas.
- Alpha cells (glucose production to raise blood glucose levels).
- Beta cells (insulin production to lower blood glucose levels).
- Delta cells (somatostatin production to suppress the release of growth hormone).
43
What are the pancreatic islet hormones?
Glucagon
Insulin
Amylin
44
When is insulin present in the blood?
When blood glucose is high.
45
Describe the functions on insulin.
- Increases glucose uptake in cells.
- Converts glucose to glycogen by glycogenesis.
- Increases amino acid uptake and protein synthesis.
- Promotes lipogenesis.
- Slows down gluconneogenesis.
- Causes blood glucose levels to drop.
46
How does hypoglycemia affect insulin?
Inhibits release of insulin.
47
When is glucagon present in the blood?
When blood glucose is low.
48
What cells does glucagon act on?
Acts on hepatocytes.
49
What are the main functions go glucagon?
- Converts glycogen to glucose by glycogenolysis.
| - Forms glucose from lactic acid and amino acids by gluconeogenesis.
50
How does hyperglycaemia affect glucagon?
Inhibits release of glucagon.
51
What is hypoglycaemia?
When blood glucose is too low
52
What is hyperglycaemia?
When blood glucose is too high
53
In what cells is Amylin stored?
Beta cells
54
Describe the secretion of Amylin.
Amylin is co-secreted with insulin when blood glucose is high.
55
What are the main functions of Amylin?
- Decreases gastric emptying.
- Supresses glycogen secretion.
- Supresses glucose production.
- Promotes satiety.
- Decreases appetite.
56
What is satiety?
The feeling of fullness
57
What causes Type 1 (IDDM) diabetes?
Pancreas fails to produce insulin due to loss of beta cells. Amylin is also reduced in this scenario.
58
What causes Type 2 (NIDDM) diabetes?
Failure to respond to insulin. Can have lower response to insulin or insufficient insulin produced.
59
What causes Alzheimers (brief)?
Glucose metabolism fails at the CNS level.
60
What type of diabetes does diabetes of pregnancy resemble?
Type 2
61
What is diabetes of pregnancy?
Onset during pregnancy, resolves postpartum.
62
What are the possible transplants used to treat type 1 diabetes?
- Islet cell transplants
- Partial pancreas transplant
- Full pancreas transplant
63
What are the positives and negatives of islet cell transplants to solve type 1 diabetes?
N- 90% of people require insulin treatment after 5 years.
P -May delay insulin treatment requirement.
64
What are the positives and negatives of partial pancreas transplants to solve type 1 diabetes?
P - prevents kidney from damage.
N - Kidneys from relatives are preferred.
65
What are the positives and negatives of full pancreas transplants to solve type 1 diabetes?
N - 50% rejected, limited by the effects of immunosuppressive medications.
66
How do the treatments for Type 1 diabetes work?
Treatments mimic physiology - insulin dosage is taken when you eat and a basal dose given once per day.
67
Why must insulin be given as an injection to people with Type 1 diabetes?
Insulin is a peptide hormone and won't survive in the stomach.
68
What are the dangers of having too much Amylin in the blood?
Cell death caused by amylin fibres.
69
What is parmlintide and what is it used for?
An analog of amylin that improves postprandial blood glucose.
70
Why is pramilintide beneficial rather than amylin?
It overcomes the tendency of human amylin to;
- Aggregate and form insoluble particles.
- Adhere to surfaces
71
What are the positive effects of Parmlintide in the body?
- Reduces HBA1c
- Reduces insulin requirement
- Reduces body weight
72
How is Type 2 (NIDDM) diabetes characterised?
- Relentless deterioration of pancreatic beta cell function leading to an initial over production of insulin.
- Insulin resistance
73
What is step 1 in the treatment of Type 2 (NIDDM) diabetes? And what are the positives and negatives of this treatment
Lifestyle changes to decrease weight and increase activity.
P- low cost
N- fails for most in 1st year
74
What is step 1 in the treatment of Type 2 (NIDDM) diabetes?
Additional medical therapies
75
What are the sites of action of drugs used for treating type 2 (NIDDM) diabetes and what is the general cause at each of these sites?
- Liver (to change glucose production).
- Pancreas (to stimulate insulin secretion)
- Adipose tissue (to alter the glucose uptake).
- Muscle (to alter glucose uptake)
- Intestine (to modify glucose absorption)
76
What are the possible issues with monitoring glucose?
- Exercise alters glucose levels.
- Food intake variable
- Illness uses glucose
- Stress uses glucose
- Alcohol can cause hypoglycaemia
77
What are the microvascular complications associated with diabetes?
- Retinopathy (changes in vision)
- Nephropathy (changes in kidney function with may lead to renal failure).
- Neuropathy
78
What are the microvascular complications associated with diabetes?
CHD
Cerebrovascular disease
PAD
79
Describe the histological changes seen in people suffering with retinopathy.
Potential aneurysms caused by blood vessels bursting and causing tissue damage.
80
How is micro albumin used in terms of nephropathy ?
Microalbumin is a measure of albumin in the urine. If this increases, this suggests kidney function isn't normal.
81
How is hypertension define in terms of systolic and diastolic blood pressure?
SBP > 130mmHg
| DBP > 80mmHg
82
How is severe hypertension define in terms of systolic and diastolic blood pressure?
SBP >140mmHg
| DBP > 90mmHg
83
Describe the pharmacotherapy required to treat hypertension and blood pressure in terms of controlling diabetes.
ACE inhibitors and angiotensin receptor blockers required.
84
How is dyslipidaemia treated in diabetic patients?
Lifestyle modifications are recommended to improve the lipid profile of patients;
- Reduction of saturated trans fats in the diet
- Weight loss
- Increased physical activity
85
In what diabetic patients may statin therapy be used?
- Patients with overt cardiovascular disease.
| - Patients older than 40 years without CVD but with one or more risk factors.
86
What are the risk factors for cardiovascular disease (CVD)?
- Dyslipidaemia
- Hypertension
- Smoking
- Positive family history of premature CAD
- The presence of micro or macroalubimna.
87
What is the main purpose of nephropathy screening?
To reduce the risk or slow progression of nephropathy and to optimise glucose and blood pressure control.
88
Describe the Hypothalamus-Pituitary adrenal axis in terms of Cortisol.
- The hypothalamus releases corticotrophin releasing hormone (CRH) - this is passed down via the hypophyseal portal blood supply to the anterior pituitary.
- ACTH is released and acts on the adrenal glands.
- Cortisol is produced by the adrenal glands.
- Cortisol produces a range of metabolic effects which aid the stress response.
- Cortisol also feedback to the pituitary to stop producing ACTH and to the hypothalamus to stop producing CRH.
89
What type of hormone is ACTH and what gene is it produced from?
A peptide hormone produced from the POMC gene
90
What transcription factor regulates the expression of the POMC gene?
Tpit
91
How is ACTH produced ?
Specific PC1 and PC2 enzymes produce ACTH and other peptides by cleaving POMC.
92
What causes Cushing's disease?
Corticotrophinomas cause Cushing's disease which is caused by excessive glucocorticoid production.
93
What effect does Tpit mutations have?
Lead to ACTH deficiency and therefore low glucocorticoids.
94
What are the actions of POMC peptides?
- Produce ACTH
- Produce alpha-MSH and beta-endorphins
- Alpha-MSH exerts its effects through various G-protein coupled receptors
- Beta-endorphins have pain killing actions and act through opioid receptors in the same way as morphine.
95
What controls ACTH?
Hypothalamic CRH and adrenal steroids.
96
How does ACTH affect adrenal steroid production ?
Increases it
97
What diseases is excess ACTH seen in ?
Cushing's and Addison's
98
What does deficiency of ACTH cause?
Adrenal failure in the pituitary gland
99
What are the different ACTH tests?
- Circadian rhythmn
- Plasma ACTH
- Short synacthen test
- Long synacthen test
- Dexamethasone suprpression test
100
How does the plasma ACTH test indicate issues and diseases?
Levels may be very high if ACTH is being produced ectopically for example if a tumour which has the POMC gene over expressed.
101
What is produced by the cortex of the adrenal glands?
- Glucocorticoids
- Mineralcorticoids
- Androgens
102
What is produced by the medulla of the adrenal glands?
Catecholamines such as adrenaline.
103
Name the functions of glucocorticoids using the example of Cortisol.
- Increases protein catabolism.
- Increases hepatic glycogenolysis (breakdown of glycogen stores to release glucose from the liver into the blood supply).
- Increases hepatic gluconeogenesis ( increases the liver production of glucose from lactate, amino acids and pyruvate).
104
What is the effect of glucocorticoids on ACTH secretion?
Inhibits ACTH secretion by a negative feedback mechanism.
105
What is the effect of glucocorticoids on water excretion?
Permissive effect which is required for initiation of diuresis in response to water loading.
106
Where is aldosterone produced?
The cortex of the adrenal glands.
107
Describe the functions of mineralcorticoids using the example of aldosterone ?
- Increase the reabsorption of sodium from the distal tubes of the kidney.
- Have separate action promoting the excretion of potassium
- Alter distribution of sodium and potassium ions across cell membranes throughout the body.
108
What are the 2 classes of adrenal sex steroids.
Androgens
| Oestrogens
109
What is the purpose of androgens as adrenal sex steroids?
Promote formation of secondary sexual hair.
110
What are adrenal steroids produced from?
Cholesterol
111
How is Aldosterone controlled by the Renin angiotensin system?
Renin is produced by the kidney and acts to convert Angiotensinogen to Angiotensin I. This activates the angiotensin converting enzymes which converts Angiotensin I to Angiotensin II then acts on the adrenal glands to regulate aldosterone production.
112
In general, what is Addison's disease?
Hyperfunction of the adrenal glands
113
Name some causes of Addison's disease.
- Autoimmune adrenalitis (autoimmune inflammation of the adrenal glands).
- Tuberculosis
- Adrenalectomy (removal of the adrenal glands)
- Secondary tumour deposits
- Haemochromatosis
- Histoplasmosis
- Adrenal Haemorrhage
114
Name some clinical features of Addison's disease.
- Tiredness
- General weakness and lethargy
- Anorexia
- Nausea and vomitting
- Weight loss
- Dizziness and postural hypotension
- Pigmentation
- Loss of body hair in women
- Hypoglycaemia
- Depression
115
What disease does excess Cortisol lead to?
Cushing's syndrome
116
What disease does excess androgens lead to?
Androgenital syndrome
117
What disease does excess aldosterone lead to?
Conn's syndrome
118
What disease does excess Oestrogens lead to ?
Feminisation
119
What are the causes of Cushing's syndrome?
- Corticosteroids or ACTh treatment.
- Pituitary hyper secretion of ACTH.
- Adrenal adenoma
- Adrenal carcinoma
- Ectopic ACTH secretions by tumours
120
What is adrenal carcinoma?
A tumour in the adrenal glands that affects cortisol production.
121
What are the clinical features of Cushing's syndrome ?
- Truncal obesity
- Thinning of skin
- Puple striae
- Excessive bruising
- Hirsutism
- Excess hair
- Skin pigmentation
- Hypertension
- Glucose intolerance
- Muscle weakness
- Back pain
- Psychiatric disturbances
122
Describe normal cortisol production.
Production of cortisol by adrenal cortex stimulated by ACTH.
Cortisol exert negative feedback on the release of ACTH.
123
Describe Cortisol production in Cushing's disease.
- Increased ACTH secretion.
- Pituitary insensitive to feedback by normal levels to Cortisol.
- Higher levels of Cortisol required to produce negative feedback o ACTH secretions.
124
Describe cortisol production when adrenal tumours are present.
- Autonomous cortisol production.
| - High circulating levels of cortisol inhibits ACTH secretion.
125
Describe cortisol production when there is Ectopic ACTH secretion.
- High levels of ACTH secreted by tumours stimulate excessive production
- Secretion of ACTH by pituitary inhibited
126
What are the possible tests for adrenal hyper function ?
Screening tests:
- 24 hour urinary free cortisol excretion.
- Overnight/ 48 hours low dose dexamethasone suppression test.
- Insulin tolerance test.
127
What is adrenogenital syndrome?
Inherited defects in the enzymes necessary for cortisol production.
128
What factors lead to suspicions of adrenogenital syndrome ?
- Ambiguois genitalia in female neonate.
- Salt-losin crisis in neonate.
- Family history of CAH
- Hypertension in a neonate or infant
- Precocious puberty in boys
- Early appearance of pubic hair in girls.
- Secondar amenorrhoae virilizzato in adult women.
129
What are the causes of Conn's syndrome?
- Adrenal adenoma
- Bilateral hypertrophy of zone glomerulosa cells.
- Adrenal carcinoma
130
What are the clinical features of Conn's syndrome?
- Hypertension
- Muscle weakness and occasional paralysis
- Latent tetany and paraesthesiae
- Polydipsia and polyuria
131
What are the common causes of secondary hyperaldosteronism ?
- Congestive cardiac failure
- Cirrhosis of liver with ascites
- Nephrotic syndrome
- Renal artery stenosis
- Sodium losing nephritis
- Batter's syndrome
- Renin-secreting tumours
132
Where is the thyroid located?
Just below the Larynx in the neck.
133
What does the Thyroid produce? and what is the purpose of this?
T4 (Thyroxine) and T3 (Triiodothyronine) which stimulate metabolism of all our cells.
Calcitonin which decreases blood calcium concentration by inhibiting breakdown of bone.
134
Where is glycoprotein hormone produced?
Hypotrophy cells
135
What is TSH secreted in response to and what is it's main purpose.
TRH stimulation and acts at the Thyroid gland to regulate production of T4/T3.
136
What is TSH-R and what is its purpose?
A G protein couple receptor, activating the cAMP pathway to increase T4/T3 production which in turn regulates growth and metabolism.
137
What regulates TSH production?
T4/T3 negative feedback inhibition at TRH neurones and at Thyrotroph at the level of the pituitary.
138
What are the signs and symptoms of disorders of the thyroid gland?
- Weight gain
- Moon face
- Fat accumulation on the upper back
- Skin changes and delayed healing of wounds
- Mood swings
- Impaired memory or concentration
139
What is hypothyroidism?
underachieve thyroid gland
140
What is hyperthyroidism?
Overactive thyroid gland
141
What is associated with an increase in the size of the thyroid and why?
The thyroid goitre is associated with an increase in the size of the thyroid. This would be expected to be seen in hyperthyroidism when there is excessive thyroid production.
142
What is a Goiter?
A swollen thyroid gland
143
How is a goitre treated?
Radioactive iodine is used and will enter the thyroid and kill off the thyroid which produces too much hormone.
144
How is goitre treated for patients who can't undergo radiotherapy and how do each of these work?
Propythiouracil - blocks thyroid hormone synthesis.
Propranolol - blocks hormone effects and inhibits the conversion of T3 to T4
145
What usually causes Thyroiditis?
A viral infection
146
What generally indicates thyroids?
Tender thyroid with fever and malaise
147
How is thyroiditis managed?
If mild it can be managed with beta blockers but it usually managed based on specific symptoms.
148
What is Hasimoto Thyroiditis?
Inflammation of the thyroid which triggers symptoms and can produce a goitre. The inflammation could also reduce the thyroid function for a period of time
149
How is hypothyroidism treated?
25-50mcg daily of synthetic thyroxine.
150
What are the symptoms of hypothyroidism?
- Patients can be asymptomatic
- Weakness, fatigue, lethargy, decreased energy
- Cold intolerance
- Dry skin, decreased sweating, hair loss
- Constipation
- Inability to concentrate, memory loss
- Weight gain
o Food is not being metabolised for energy so is stored
- Dyspnea
- Peripheral paresthesias
- Depression
- Anorexia – become this way due to weight gain
- Muscle cramps, musculoskeletal pain
- Infertility
- Impaired glucose tolerance
o Glucose levels will rise given that the glucose will not be metabolised
- Decreased hearing
- Carpal tunnel syndrome
