| what are hormones | hormones are chemical messengers that are secreted into the blood by the endocrine glands, the hormones then travel in the blood until it reaches the target cell
Once arriving at their target cell, they bind (to their target cell) to receptors on the target cell’s membrane (signal transduction) |
| second messenger system meaning | hormones have a second messenger system, what this means is that when the hormones reach its target cell another hormone is released as it is the stimulus |
| three functions of hormones | tropic hormones can target other endocrine glands, stimulate growth hormones and secretion
sex hormones target reproductive tissue
Anabolic hormones stimulate anabolism [cause smaller molecules to develop into larger ones] so an example is GH stimulates production of bone growth |
| what is a steroid hormone | A steroid hormone is manufactured by cholesterol and are not soluble in blood, theses hormones attach to protein for transportation |
| what is a steroid hormone | A steroid hormone is manufactured by cholesterol and are not soluble in blood, theses hormones attach to protein for transportation |
| what is a non-steroidal hormone | a non steroidal hormone are manufactured by protein connects to the receptor of the target cell producing secondary hormones / messengers bringing out a cascade of effects |
| control of hormone secretion | Normally, the overall control of how much hormone is secreted is maintained via the feedback loop
Overall control is when the target cell identifies that levels have been reached & therefore stops release of the hormone targeting it |
| calcium (Ca) feed back loop using breast feeding as a example | during breast feeding calcium (Ca) is moved from the blood to the breast milk, this causes blood calcium levels to drop. the parathyroid hormone (PTH) identifies this causing otseoclasts to release Ca from the bone
once blood Ca levels return to normal the Parathyroid hormone (PTH) stops. |
| Other methods of regulating hormone release | Sometimes there is direct input from the nervous system - for example the sympathetic nervous system causes the adrenal medulla to release norepinephrine/epinephrine
another example is another hormone (produced by a separate, different gland) – pituitary gland produces Thyroid stimulating hormone (TSH) which then stimulates the thyroid gland to produce & release hormones (T3 & T4) |
| what hormones does the anterior pituitary gland produce | Growth Hormone (GH), Adrenocorticotrophic hormone (ACTH), Thyroid stimulating hormone (TSH), FSH and LH , prolactin (PRL) |
| what hormones does the posterior pituitary gland release | ADH and oxytocin (OT) |
| why is the posterior pituitary gland said to be not a true endocrine gland | the posterior pituitatry gland is not a true endocrine gland because it doesn't manufacture its own hormones, instead it is an extension of the hypothalamus. the hormones are manufactured in the hypothalamus and travel to the posterior pituitary gland to be stored and the release is controlled by neurons |
| why is the anterior pituitary gland a true endocrine gland | the anterior pituitary gland manufactures its own hormones but its release is not controlled by neurons, but controlled by the blood portal circulation by the hypothalamus |
| hormones produced by the hypothalamus chain reaction meaning | hormones produced by the hypothalamus travel to the the anterior pituitary gland through the hypophyseal portal system, this hormones then allows the anterior pituitary gland stimulate the release of its hormones which then go on to other gland of the endocrine system and stimulate the release of another hormone and or reach its target cell |
| what are the 5 classifications that the anterior pituitary gland produces | somatrotrophs, corticotrophins, thyrotrophs, gonadotrophins, lactotrophins |
| function of somatrotrophs hormone that the hypothalamus produce then secrete in to the anterior pituitary which secrete which hormone and function of that hormone? | secrete growth & somatropin hormone (GH/STH), in the anterior pituitary gland and the target cell is bone |
| function of corticotrophins hormone that the hypothalamus produce then secrete in to the anterior pituitary which secrete which hormone and function of that hormone? | the function of cortricotrophins is to secrete adrenocorticotriphins (ACTH) this hormones target cell is the adrenal cortex which stimulates the release of cortisol |
| function of thyrotrophs hormone that the hypothalamus produce then secrete in to the anterior pituitary which secrete which hormone and function of that hormone | Thyrotrophs secrete thyroid stimulating hormone (TSH) target cell thyroid gland. The thyroid gland then releases T3 and T4 cells |
| function of gonadotrophins hormone that the hypothalamus produce then secrete in to the anterior pituitary which secrete which hormone and function of that hormone | Gonadotropin releasing hormone stimulate (GnRH) the release of luteinizing hormone (LH) & follicle stimulating hormone (FSH), target cells include the testes & ovaries |
| function of lactotrophins hormone that the hypothalamus produce then secrete in to the anterior pituitary which secrete which hormone and function of that hormone | Lactotrophins secrete Prolactin releasing hormone (PRH) and stimulates the release of prolactin, target cell is the mammary glands in the breast |
| function of somatotrophins (STH) / Growth hormone (GH) | the function of somatotrophins (STH) and growth hormone (GH) is it promotes body growth by stimulating the liver and other tissue to produce another hormone called insulin-like hormone factor 1 |
| function of thyroid stimulating hormone (TSH) | the function of thyroid stimulating hormone promotes and maintains the growth and development of the thyroid & contributes to the release of thyroid hormone |
| function of adrenocorticotrophic hormone (ACTH) | Adrenocorticotropic hormone (ACTH) - promotes and maintains normal growth and development of the cortex of the adrenal gland. It also stimulates the adrenal cortex to manufacture and secrete some of its hormones |
| where are the adrenal glands located | the adrenal glands are located over the kidneys, their are two divisions of the adrenal gland which is called the adrenal cortex and adrenal medulla |
| what are the hormones released from the adrenal cortex | Adrenal cortex secrete three groups of hormones called adrenocortical hormones
These include mineralocorticoids, glucocorticoids, & gonadocorticoids (sex hormones)
The gonadocorticoids affect sexual drive, sexual characteristics. These hormones are produced throughout life |
| what hormones does the adrenal medulla release | The adrenal medulla is composed of neuro-secretory tissue : epinephrine & norepinephrine (these 2 hormones are also Neurotransmitters in the nervous system for the adrenergic pathway])
So during the fight / flight response the medullary cells release 2 hormones into the blood – epinephrine & norepinephrin |
| function of Glucocorticoids a group of hormone released from the adrenal cortex | The main hormone is cortisol (stress hormone) cortisol releases glucose into the blood
In times of stress, they promote hyperglycaemia so that skeletal muscles receive adequate glucose
Promote gluconeogenesis – protein metabolism. May influence tissue wasting (via loss of proteins) & hyperglycaemia
Promote gluconeogenesis via lipid metabolism |
| what happens when your stress | the hypothalamus releases corticotrophin releasing hormones which then reaches it target cell being the anterior pituitary gland which stimulates the release of ACTH, ACTH reaches the adrenal cortex stimulating the release of cortisol
the hypothalamus senses the amount of cortisol in the blood causing glucose to be released from the liver |
| what hormones are released from the adrenal medulla | the hormones released from the adrenal medulla are norepinephrine and epinephrine |
| definition of stress and what is stress | “Nonspecific response of the body to any demand or change”
Stress hormones are released, attach to receptors & interact with the body’s cells to bring about a result
Once the stress is relieved, levels decrease (-ve feedback mechanism) |
| causes of stress | lifting something heavy, nutrient deprivation during times of fasting or O2 deprivation during changes in atmospheric conditions, can be emotional eg about to sit an exam, |
| what are some normal things that may happen in the body during times of stress | Energy created, the liver is more active in preparation of glucose release
HR increases, pumping more blood (O2) to muscles
Arteries constrict increasing BP
Veins dilate to push blood back to the heart |
| what is acute stress | Results from events/situation that pose a threat
Involve unpredicted events
Leaves the person with a diminished sense of ‘control’ |
| what is chronic stress | Repeated exposure to the stressor(s)
Can leave the person feeling on the ‘edge of a cliff’ where something will easily push ‘you’ over the edge
continues high cortisol levels |
| what are the three phases of stress response | alarm, adaption and exhaustion phases |
| explain the alarm phase of the stress response | the alarm phase involves 2 body systems the sympathetic and endocrine system
the sympathetic is an immediate response causing nor/epinephrine to be released from the adrenal medulla
the endocrine system is a slower response, cortisol is released through the adrenal cortex through a series of other hormones being released causing glycogen to be converted into glucose to be moved into the muscles |
| explain the adaption phase of the stress response | where the body undergoes some learning
Overtime the person begins to learn the stressor is not as threatening as first thought
The person adapts to the stressor and will no longer stimulate the sympathetic n/s and the adrenal cortex |
| explain the exhaustion phase of the stress response | A situation where the person does not learn to adapt & continues to perceive the stressor as a threat
Results in continuing cortisol secretion, blood levels remain raised in the body for a length of time
Eventually the levels do drop
The consequences of this are stress exhaustion |
| when the person does not learn to adapt to the stressor stress exhaustion occurs what are the 3 body disruptions | Stress exhaustion is associated with long term/chronic stress
Linked to 3 stages of body disruption
Chronic inflammation causes damage to many of the body’s tissues (autoimmune component)
An acceleration of aging cells resulting in the body’s ability to repair DNA. which causes an increase in genetic mutations
An increase in oxidative has been linked to degenerative changes in the brain |
| what is the function of calcitonin | the function of calcitonin is to regulate blood calcium levels, when blood calcium levels increase calcitonin increases Ca uptake into the bone through osteoblast
which lowers calcium levels in the blood |
| what is the function of insulin | insulin is a hormone produced by the beta cells in the pancreas, the function of insulin is to move glucose into tissues to used as energy or
insulin moves glucose into the liver to be converted into glycogen to be stored in the liver until needed
which causes BGL to drop |
| what is the function of glucagon | glucagon is hormone produced by alpha cells in the pancreas, the function of glucagon is to convert glycogen in the liver back to glucose to be used by tissues and muscles in the body, this causes BGL to rise |
| function of the thyroid gland | the thyroid gland is located anterior to the trachea and inferior the larynx. its function is it regulates the metabolic rate of all cells
ts release is controlled by thyrotropin (TRH) coming from the hypothalamus
TRH travels to the posterior pituitary & releases / secretes Thyroid stimulating hormone (TSH)
TSH targets the thyroid gland
The thyroid gland produces thyroid & calcitonin |
| thyroid hormone what are the two called | T3 and T4 are the two classifications
Target cells found throughout the body, particularly brain, heart, muscles making them active in metabolic processes, cell growth
Need a carrier in blood, namely immunoglobulin & albumin
When they near their target cell they detach from their carrier & enter the target cell |
| function of the parathyroid | 4 parathyroid glands are located on the posterior of the thyroid gland
Their function is to secrete parathyroid hormone (PTH) |
| function of parathyroid hormone (PTH) | the function of PTH is to regulate blood calcium levels, when blood calcium levels are low PTH increases bone break down which releases calcium into the blood
It also produces a form of Vitamin D in the kidneys therefore increases Ca diffusion via the small intestine therefore increasing Ca levels |
| function of parathyroid hormone (PTH) | the function of PTH is to regulate blood calcium levels, when blood calcium levels are low PTH increases bone break down which releases calcium into the blood
It also produces a form of Vitamin D in the kidneys therefore increases Ca diffusion via the small intestine therefore increasing Ca levels |
