endocrine

Question 1

hormones

Answer 1

chemical signals that travel in blood or lymph and act at a distance

Question 2

hormone action

Answer 2

can include:

• altering plasma membrane permeability of membrane potential by opening or closing ion channels
• stimulating synthesis of proteins or regulatory molecules
• activating or deactivate enzyme systems
• inducing secretory activity
• stimulating mitosis

Question 3

hormone release (humoral stimuli)

Answer 3

• changing blood levels of ions and nutrients directly stimulates secretion of hormones

Question 4

hormone release (neural stimuli)

Answer 4

• nerve fibres stimulate hormone release, such as when sympathetic fibres stimulate the adrenal gland to release adrenaline

Question 5

hormone release (hormonal stimuli)

Answer 5

• hormones stimulate other endocrine organs to release their hormones
  0 for example, hormones form the hypothalamus stimulate further release of other hormones from many endocrine glands

Question 6

anterior pituitary gland

Answer 6

• receives signals from the hypothalamus by a series of blood vessels known as hypophyseal portal system
• these vessels carry releasing and inhibitory hormones down from the hypothalamus to the anterior pituitary to regulate its action
• anterior pituitary then produces and releases the hormones required

Question 7

posterior pituitary gland

Answer 7

• directly receives hormones from the hypothalamus

- stores and releases hormones

Question 8

anterior pituitary hormones

Answer 8

• Adrenocorticotropic hormone (ACTH) which acts on the cortex of the adrenal gland, prompts release of many hormones that play a role in stress, and glucose, water and salt balance
• Prolactin (PRL) stimulates milk production in the mammary glands
• Follicle-stimulating hormone (FSH) prompts the gonads to mature and release ova and sperm
• Lutenizing hormone (LH) prompts gonads to secrete sex hormones like oestrogen and testosterone

Question 9

posterior pituitary hormones

Answer 9

• they are released in response to hypothalamic input
• Anti-diuretic hormone (ADH) conserves water and affects electrolyte balance, targets the kidney to decrease production and release of urine
• Oxytocin, targets smooth muscles (stimulates uterine contractions during childbirth, also triggers milk ejection in women producing milk

Question 10

thyroid gland

Answer 10

• thyroid lies around the windpipe below the larynx
• composed with follicles of colloid thyroglobin and iodine
• colloid is the precursor of thyroid hormone

Question 11

thyroid hormone

Answer 11

• 2 related hormones (T3 and T4)
• thyroid hormone release is regulated by negative feedback
• major metabolic hormone that increases metabolic rate and heat production
• also plays a role in maintenance of blood pressure, regulation of tissue growth, development of skeletal/nervous systems and reproductive capabilities

Question 12

pancreas

Answer 12

• triangular gland located inferior and posterior to the stomach in the abdominal cavity
• 99% exocrine in function
• important endocrine gland, referring to blood glucose levels, pancreatic islets

Question 13

glucagon

Answer 13

• major target is the liver, where it promotes
• glycogenolysis - breakdown of glycogen to glucose
• the release is stimulated by falling blood glucose and sympathetic stimulation, rising blood amino acid levels

Question 14

insulin

Answer 14

• lowers blood glucose levels by the acceleration of glucose uptake and glucose metabolism
• stimulation of glycogen synthesis and conversiom of glucose to fat
• participates in neuronal development and leanring and memory
• release is stimulated by rising blood glucose

Question 15

adrenal glands

Answer 15

• paired, pyrimid-shaped organs atop the kidneys

Question 16

parathyroid and pineal glands

Answer 16

parathyroid - tiny glands embedded in posterior thyroid - produce the most important Ca balance hormone parathyroid hormone (PTH). it stimulates osteoclasts to digest bone matrix, enhances reabsorption of Ca2+ and secretion of phosphate by kidneys
pineal - small gland hanging from roof of third ventricle

Question 17

gonads

Answer 17

• produce steroid sex hormones
• ovaries produce oestrogen and progesterone responsible for maturation of female reproductive organs, appearance of secondary sexual characteristics, breast development and cyclic changes
• testes produce testosterone responsible for maturation of male reproductive organs, sex drive, sperm production

Question 18

other hormone producing structures

Answer 18

• heart, ANP (blood pressure, volume and Na+)
• gastrointestinal tract (hormones that locally effect digestive activity)
• skin, cholecalciferol (precursor of Vit D)
• adipose tissue, leptin (involved in appetite control and energy expenditure
• kidneys (erythropoiten signals production of red blood cells and Renin is involved in blood pressure
• thymus, organ in thorax (involved in development of immune cells and system)

Question 19

growth hormone imbalances

Answer 19

• excessive secretion during childbirth (gigantism)
• excessive secretion during adulthood (acromegaly)
• reduced/inhibited secretion during development (pituitary dwarfism)

Question 20

antidiuretic hormon ADH imbalances

Answer 20

• deficiency (Diabetes insipidus; huge output of urine and intense thirst)
• Hypersection (syndrome of inappropriate ADH secretion)

Question 21

thyroid hormone imbalances

Answer 21

• hyposecretion in adults (myxoedema; endemic goiter if due to lack of iodine)
• hyposecretion in infants (cretinism)
• hypersecretion (Grave’s Disease)

Question 22

adrenal cortex glucocorticoids imbalances

Answer 22

• Hypersecretion (Cushing’s syndrome) depression of inflammation, immunity, skeletal tissue
• Hyposecretion (Addison’s disease) decrease in glucose and Na+ levels

Question 23

insulin imbalances

Answer 23

• Diabetes
• type 1 = insulin dependant (hyposecretion or absence of insulin - problem with pancreas, potential genetic or immune deficiency)
• type 2 = non-insulin dependent (dificient effects or activity of insulin - often lifestyle related - insulin resistance)
• glucose concentrations exceed renal absorption due to inability to reduce blood sugar levels
• hyperinsulinism is excessive insulin secretion, results in hypoglycemia, disorientation or unconsciousness

Question 24

parathyroid hormone (pth) imbalances

Answer 24

• hyperparathyroidism due to tumor (excessive Ca2+ resorbed - bones soften and deform, Elevated blood Ca2+ depresses nervous system and contributes to formation of kidney stones)
• Hypoparathyroidism following gland trauma or removal (results in tetany, respiratory paralysis and death)

Question 25

neurons vs hormone

Answer 25

NEURON
- transmit electrically
- use chemicals to pass on to next cell causing stimulation/inhibition
- immediate response time
- impulses sent quickly
- highly branched and connected
HORMONES
- blood-borne and can affect cells near and far
- response time can take seconds to years
- hughly regulated by negative feedback
- multiple modes of affecting cell metabolism