chpt 10.1&10.2 test Flashcards
JAN 10
Hormones act as chemical messengers which enable
one part of the body to give instructions to another part
Local regulators act on – and may even self regulate, producing chemicals to –.
nearby cells rather than cells some distance away, stimulate their own cellular processes.
Hormones are secreted by the …
cells, tissues, and organs that compose the endocrine system
The endocrine system regulates and coordinates – and contributes to the control of –
- the functions of organs throughout the body
- growth, development, reproduction, behaviour, energy metabolism, and water balance
The nervous and endocrine systems are — related, but they control — in different ways.
- structurally, chemically, and functionally
- organ and tissue functions
The nervous system sends – and the speed of these nerve impulses enables an organism to interact rapidly with its external environment.
fast electrical signals along the nerves
The endocrine system uses hormones, with — so that hormones are released when needed.
slower/ longer-acting responses (to control organ and tissue functions and itself has to be controlled)
The nervous system can regulate –, it ultimately controls the –.
the release of most hormones, actions of the endocrine system
Endocrine glands are…
ductless secretory organs that secrete their hormones directly into the blood or extracellular fluid
Exocrine glands (such as the sweat and salivary glands) release their secretions into …
ducts that lead outside the body or into the body cavities
Hormones are then —. Most body cells are constantly exposed to a wide variety of hormones.
circulated throughout the body in the blood and other body fluids
Target cells will respond to a specific hormone because …
only they have receptor proteins that recognize and bind to that type of hormone.
Hormones are cleared from the body at a — by —…
- steady rate
- enzymatic breakdown in target cells/blood, or/organs and the breakdown products are reused or excreted.
There are more than — known hormones and local regulators in humans. Hormones are identified by their —.
60, chemical structure
Protein hormone is a hormone composed of —. It usually acts on —.
- chains of amino acids (3-200+) that is water soluble
- cell membrane receptors
protein hormone: produced in —, released into —, usually hydro— and —- through the blood and intercellular fluids.
— regulate the division and differentiation of many types of cells in the body
endocrine glands, blood/extracellular fluid, -philic, diffuse well, Growth factors
Steroid hormone is a hormone composed of — that is —. It usually passes through —.
cholesterol, not very water soluble, the cell membrane and acts on receptors inside the cell
steroid hormone:
-pass/diffuse —
-combine with hydrophilic carrier proteins to form —
- include aldosterone, cortisol, and the sex hormones.
Some similar structures but — (testosterone and estradiol). differ only in —
easily, water-soluble complexes, very different effects, the presence or absence of a single methyl group.
Many hormones are secreted in an inactive or less active form called — which are converted by the —
prohormones, target cells or by enzymes in the blood or other tissues to the active form.
— are commonly synthesized as pro-hormones and then are converted to the active form in the source cell.
Protein hormones
Blood Pressure Hormone:
Angiotensin
secreted by the — as angiotensinogen —> an — cleaves an inactive form of angiotensin from angiotensinogen —> inactive form is converted to the active hormone by the angiotensin-converting enzyme (ACE) —> results in —
liver, enzyme, an increase in blood pressure.
— are often prescribed to control high blood pressure
ACE inhibitor
Hormones are usually secreted in —, but a process of — magnifies their effects.
relatively small amounts, amplification (Once a receptor cell activates a few proteins, these proteins activate other proteins, each of which activates other proteins, and so on. )
The secretion of most hormones is regulated by —
negative feedback mechanisms
Negative Feedback Mechanism = a chemical that is affected at the end of the action pathway of a hormone controls the further action of the hormone by —
inhibiting an earlier chemical reaction.
A response in a feedback loop may be — of a substance or a — of a substance.
the production, decrease in the production
Hypothalamus releases —(TRH), which initiates a —. As the concentration of the thyroid hormone in the blood increases, it inhibits an earlier step in the pathway, the secretion of — (TSH) by the pituitary gland.
thyroid-releasing hormone , pair of hormone releases by the pituitary and thyroid glands, thyroid-stimulating hormone
Some glands —, and many body processes are affected by —.
produce multiple hormones, more than one hormone at a time
Blood concentrations of — are regulated by the coordinated activities of several hormones, which are secreted by different glands.
glucose, fatty acids, and calcium, potassium and sodium ions
In many systems, negative feedback loops adjust the — in their effects that maintains homeostasis in the body. Five separate hormone systems such as the — all act together in a coordinated fashion to keep the body’s fuel levels in balance between meals.
- level of secretion of hormones that act in opposing ways and creates a balance,
- digestive tract, pancreas, nervous system, and pituitary and adrenal glands,
Protein hormones bind to receptor molecules in the cell membrane, causing …
the receptor molecule to change shape.
Mechanism: a. Hormone binds to —.
b. Activated receptor triggers a —
c. Signal leads to —.
- surface receptor and activates it
- signal pathway (signal passes into the cell and causes further changes, ex. release of enzymes that add phosphate groups, activating/ deactivating them)
- cellular response (may act in the cytosol only, or it may affect the nucleus of the cell)
Protein hormone: Glucagon (pathway)
glucagon binds to surface receptors on liver cells —> triggers a series of reactions
—> lead to the addition of phosphate groups —> activate the enzyme —> breakdown of stored glycogen into glucose
Glucagon is a hormone produced by — that r— by promoting the breakdown of glycogen in the liver.
alpha cells in the pancreas, raises the blood glucose level
Steroid hormones are — so they pass easily through the plasma membrane.
lipid based and lipid soluble
Steroid hormones attach to — in the cytosol or nucleus of a cell and form a —then binds to a — on a specific gene, turning the gene’s action on or off.
receptors, hormone receptor complex , control sequence
Activation and deactivation of the gene changes the —, which changes the —
amount of protein that it synthesizes, cellular activity.
lipid soluble hormones: mechanism
a. Hydrophobic hormones pass freely through plasma membrane.
b. binds to the receptor.
c. Hormone-receptor complex binds to control sequence of gene, leading to gene activation/inhibition.
steroid hormone: aldosterone (pathway)
blood pressure falls below normal levels —> aldosterone is secreted by adrenal glands —> travels through cell membranes —> attaches to specific receptors —> receptor acts as a transcription factor for a specific gene —> synthesis of proteins —> increase sodium reabsorption in blood —> increases water retention —> increase blood pressure
A single target cell may have …
receptors for several hormones and respond differently to each hormone.
Liver cells of vertebrates have …
receptors for the pancreatic hormones insulin and glucagon
Insulin increases the — resulting in a decrease in —
uptake of glucose and its conversion to glycogen, blood glucose level.
Glucagon stimulates — resulting in an —.
the breakdown of glycogen into glucose, increases in blood glucose level
Particular hormones can interact with — in or on a range of target cells. — are then triggered in each target cell because the receptors trigger different signal pathways
different types of receptors, Different responses
The response to a hormone may differ among species. EX- Melatonin
- is important in regulating daily and annual cycles in most animals
-yet, plays a role in regulating the salt glands of marine birds.
Mechanisms by which hormones work have four major features:
a. Only the cells that contain surface/ internal receptors for the hormones will respond.
b. Once bound to receptors, hormones produce response by turning cellular processes on or off. (by altering the proteins that are functioning in or produced)
c. Hormones are effective in very small concentrations (amplification occurs in both the surface and internal receptor mechanisms)
d. The response to a hormone differs among target organs and species.
The body contains –, each tailored to a specific task or sometimes more than one task. Hormones, which are produced by –, are like a – for the body.
dozens of different hormones, the endocrine system, chemical management system
The endocrine system …
is a system of glands located in various parts of the body, produce hormones and secrete them into the bloodstream, which carries them throughout the body.
Major Endocrine Glands in Humans:
a) Hypothalamus (part of nervous system)
b) Anterior pituitary and posterior pituitary
c) Adrenal glands (cortex and medulla – secrete different hormones)
d) Ovaries (female gonads)
e) Tests (male gonads)
f) Pineal gland
g) Thyroid gland
h) Parathyroid glands
i) Islets of Langerhans (pancreas)
Organs Containing Endocrine Cells:
a) Thymus
b) Heart
c) Liver
d) Stomach
e) Kidneys
f) Small intestine
The hypothalamus is …
the region of the brain that releases hormones to control the pituitary gland, which, in turn, controls other endocrine glands
A neurohormone is …
- a hormone produced by neurons (nerve cells) that controls the production of other hormones in the pituitary gland
- travel along the length of the nerve cells, diffuse into the bloodstream, and then travel through the blood into the pituitary gland.
The hypothalamus is controlled by…
input from other parts of the nervous system
- some neurons connect directly to the hypothalamus from sensory receptors that monitor blood for changes in body chemistry or temperature.
Input to the hypothalamus also comes from —. Negative feedback systems help to control how the hypothalamus releases its hormones.
numerous connections from control centres elsewhere in the brain
(hypo) Hormones Produced: releasing and inhibiting hormones such as the —
Target Tissue: —
Function: regulates the secretion of —
growth hormone–releasing hormone (GHRH) or growth hormone–inhibiting hormone (somatostatin), anterior pituitary, anterior pituitary hormones
The pituitary gland is …
- two-lobed gland within cranial cavity that produces hormones that control the other endocrine glands
- has two major lobes; anterior lobe and the posterior lobe.
Neurohormones travel through a — that connects —
portal vein, capillaries inside the hypothalamus with the capillaries inside the anterior pituitary gland.
The portal vein provides a critical link between the —, because most of the blood that enters the anterior pituitary gland must first pass through the hypothalamus.
nervous system and the endocrine system
Two types of neurohormones produced by the hypothalamus are the —. These hormones either — the release of specific hormones that are created in the anterior pituitary gland.
releasing hormones and inhibiting hormones, stimulate or inhibit
Hormones secreted by the endocrine cells inside the anterior pituitary gland are then —
released into the bloodstream to reach their target tissues, where they control many other endocrine glands/some bodily processes.
The hormones secreted by the anterior pituitary gland control endocrine glands elsewhere in the body and are referred to as —.
tropic hormones
The anterior pituitary hormones are controlled by the —.
releasing or inhibiting hormones that come from the hypothalamus
Hormones Produced: prolactin (PRL)
Target Tissue: —
Function: —
mammary glands , stimulates breast development and milk production
Prolactin influences — in vertebrates. In all vertebrates, prolactin has a role in promoting both maternal and paternal behaviour. In non-mammalian vertebrates, as in fish it is one of the hormones that controls water balance.
reproductive activities and parental care, controls water balance
Hormones Produced: growth hormone (GH)
Target Tissues: —
Function: —
bone/ soft tissue, stimulates the growth of bones and soft tissues; helps to control the metabolism of glucose and other fuel molecules
The growth hormone stimulates — in children and adolescents and stimulates — in adults.
-cell division, protein synthesis, and bone growth
-protein synthesis and cell division
The growth hormone binds to –, causing them to release —, a protein hormone that directly stimulates the growth processes.
muscle and other target tissues, insulin-like growth factor (IGF)
The growth hormone directly controls a many major metabolic processes in mammals of all ages, including the conversion of …
glycogen to glucose and fats to fatty acids as a means of regulating their levels in the blood
The growth hormone stimulates body cells to take up — and limits the rate at which —.
fatty acids and amino acids, muscle cells can take up glucose
In humans, deficiencies during childhood produce —- caused by —, who remain small in stature, and overproduction during childhood or adolescence produces—.
pituitary dwarfs, a tumour of the anterior pituitary, pituitary giants, who may grow up to 2.7 m in height.
Hormone: thyroid-stimulating hormone (TSH)
Target Tissue: —
Function: stimulates the —
thyroid gland , secretion of thyroid hormones and the growth of the thyroid gland
Hormone Produced: adrenocorticotropic hormone (ACTH)
Target Tissue: —
Function: stimulates the secretion of —-
adrenal cortex, glucocorticoids by the adrenal cortex
Hormone Produced: follicle-stimulating hormone (FSH)
Target Tissue: —
Function: —
ovaries in females, testes in males, - stimulates egg growth/ development and secretion of sex hormones in females; sperm production in males
Hormone Produced: luteinizing hormone (LH)
Target Tissue: —
Function: regulates —
ovaries in females/ testes in males , ovulation in females and the secretion of sex hormones in males
Hormone Produced: melanocyte-stimulating hormone (MSH)
Target Tissue: —
Function: —
melanocytes in the skin of some vertebrates, promotes darkening of the skin
Hormone Produced: endorphins
Target Tissue: —
Function: —
pain pathways in the nervous system, inhibit the perception of pain
The posterior lobe of the pituitary gland stores and releases — when the appropriate nerves from the hypothalamus are stimulated. These hormones are transferred to the posterior pituitary gland along —
antidiuretic hormone and oxytocin into the bloodstream, nerve cells that reach from the hypothalamus into the posterior pituitary.
Hormone Produced: antidiuretic hormone (ADH)
Target Tissue: —
Function: —
kidneys, increases blood volume and pressure by increasing water reabsorption in the kidneys
Antidiuretic hormone is released when sensory receptor cells of the hypothalamus —
detect an increase in the blood’s sodium ion concentration after a salty meal or when the body is dehydrated.
— inhibit the antidiuretic hormone and — stimulate the antidiuretic hormone secretion and water retention.
Ethanol and caffeine, nicotine and emotional stress
The antidiuretic hormone helps maintain blood pressure by —
reducing water loss, causing blood vessels in some tissues to constrict and enable the kidneys to maintain a homeostatic balance of extracellular fluid
Approximately — of the water filtered into the nephron is reabsorbed in the proximal convoluted tubule. The remainder is –, but only if ADH is present. It is the control of this volume of water (15 %) in the kidneys that balances the concentrations of the body fluids.
85 %, absorbed in the distal convoluted tubule
Similar hormones secreted in fish, amphibians, reptiles, and birds. In amphibians, the antidiuretic like hormone increases —.
the amount of water that enters the body through the skin and from the urinary bladder
Hormone Produced: oxytocin
Target Tissue: —
Function: —
uterus/ mammary glands ,
- promotes uterine contractions; stimulates milk release from the breasts
The pituitary gland is sometimes referred to as the —- because it produces hormones that control most of the other endocrine glands.
“master gland”
The anterior pituitary secretes several major hormones into the bloodstream, some of which —.
drive hormone secretion in other glands
The posterior lobe of the pituitary gland stores and releases —, one of which helps to control blood pressure.
two important hormones
