Chemical Coordination: Endocrine System Flashcards
second great integrative system that controls an animal’s activities and communicates through chemical messengers known as hormones.
Endocrine system
Endocrine system is composed of various organs called what
glands
- chemical substances that are released into the blood in small amounts
- carried throughout the body by the circulatory system to distant target cells where they initiate physiological responses
hormones
- small, well-vascularized ductless glands composed of groups of cells arranged in cords or plates
- organ that produces hormones that are released into the bloodstream and travel to tissues and organs throughout the body
endocrine glands
have ducts for discharging their secretion onto a free surface
exocrine glands
ex. of exocrine glands
- sweat glands
- sebaceous glands
- salivary glands
Determines if the hormones cause widespread or extremely specialized reactions and at specified times
receptor molecules
Two kinds of receptors
- membrane-bound receptors
- nuclear receptors
- specialized protein molecules attached to or integrated into the cell membrane
- through interaction with specific ligands, they facilitate communication between the cell and the extracellular environment
Membrane receptors
What are the second-messenger systems known to participate in hormone actions
- cyclic AMP
- cyclic GMP
- calmodulin
- inositol trisphosphate
- diacylglycerol
family of ligand-regulated transcription factors that are activated by steroid hormones, and various other lipid-soluble signals
Nuclear receptors
- recognize short stretches of double-helical DNA of defined sequence
- determine which of the thousands of genes in a cell will be transcribed
Gene regulatory proteins
regulate color changes, growth, reproduction, and internal homeostatic mechanisms, such as metabolism, metabolic fuel levels, and osmoregulation
invertebrate hormones
Ex. of hormones in invertebrates
- peptides (often neuropeptides)
- steroids
- terpenoids (lipid-soluble organic molecules)
- principal source of hormones in many metazoan phyla
- resemble non-neural endocrine cells in their actions
- release hormones into the circulation and regulate a number of physiological responses
Neurosecretory cells
- products of neurosecretory cells and these are discharged directly into the circulation
- serve as a crucial link between the nervous and endocrine systems
Neurosecretory hormones
increases heart rate in Crustacea
Cardioactive peptide
hormones that regulate metabolism of carbohydrates, fats, and amino acids in Crustacea
Crustacean Hyperglycemic Hormone (CHH)
hormones that regulate metabolism of carbohydrates, fats, and amino acids in insects
Adipokinetic Hormone family
stimulate the secretion of fluid in insect Malpighian tubules
Diuretic hormones
- known to regulate muscular tissues of the body, and digestive and reproductive processes in many invertebrates, as well as osmoregulatory processes in nematodes, annelids, molluscs, and insects, and arterial hemolymph flow in crustaceans
- family of small neuropeptides
- appears to have evolved as early as bilateral symmetry
FMRFamide-related peptides (FaRPs)
These are primary controlled by the interaction of two hormones. One favoring growth and differentiation of adult structures and another favoring retention of juvenile structures
- molting
- metamorphosis
- steroid produced by the prothoracic gland
- controlled by prothoracicotropic hormone or PTTH
- polypeptide produced by neurosecretory cells of the brain, and transported by axons to the corpora cardiacum where it is stored.
- molting hormone or
- ecdysone
Molting hormone is also called as
ecdysone
Molting hormone or ecdysone is produced by what gland
prothoracic gland
Molting hormone is controlled by what
prothoracicotropic hormone (PTTH)
- terpenoid produced by the corpora allata
- appears to be important, at least in some insects, during diapause (or arrested development), which can occur at any stage of metamorphosis
juvenile hormones
Juvenile hormones are produced by what
corpora allata
usually occurs due to seasonal changes in environmental conditions, such as cold temperatures or changes in day length
Diapause
- small gland lying in a well-protected position between the roof of the mouth and floor of the brain
- two-part gland having a double embryological origin
Pituitary gland (hypophysis)
Pituitary gland is also called as
hypophysis
Two main sections of the pituitary gland
- Anterior pituitary (adenohypophysis)
- Posterior pituitary (neurohypophysis)
Anterior pituitary is also called as
adenohypophysis
Posterior pituitary is also called as
neurohypophysis
- front lobe of your pituitary gland
- produces and releases hormones
anterior pituitary
- does not produce hormones per se—this is done by nerve cells in the hypothalamus—but it does release them into the circulation
- store and release the hormones oxytocin and vasopressin (antidiuretic hormone)
posterior pituitary
contains groups of neurosecretory cells, which are specialized nerve cells that manufacture neurohormones called releasing hormones or release-inhibiting hormones (or “factors”)
hypothalamus
What are the neurohormones the hypothalamus manufacture
releasing hormones or release-inhibiting hormones
What does the hypothalamus manufacture
neurohormones
stop and start the production of other hormones throughout the body
releasing hormones or release-inhibiting hormones
Lobes of the anterior pituitary
- Anterior lobe (pars distalis)
- Intermediate lobe (pars intermedia)
How many hormones does the anterior pituitary produce
seven (7)
The seven (7) hormones produced by the anterior pituitary
- Thyroid-stimulating hormone (TSH) or thyrotropin
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Adrenocorticotropic hormone (ACTH)
- Prolactin
- Growth Hormone (somatotropin)
- Melanocyte-Stimulating Hormone (MSH)
Thyroid-stimulating hormone is also called as
thyrotropin
stimulates production of thyroid hormones by the thyroid gland
thyroid-stimulating hormone (TSH) or thyrotropin
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are commonly known as what
gonadotropins
tropic hormones that act on
the gonads (ovaries of females, testes of males)
gonadotropins
group of hormones that stimulate other endocrine glands so as to produce their particular hormones
Tropic hormones
- promotes egg production
and secretion of estrogen (females) - supports sperm production (males)
Follicle-stimulating hormone (FSH)
- induces ovulation, corpus luteum production, and secretion of female sex steroids, progesterone and estrogen (female)
- promotes production of male sex steroids (primarily testosterone) (male)
Luteinizing hormone (LH)
Before it was discovered to be identical to LH in females, what was it once called in males?
Interstitial cell stimulating hormone (ICSH)
increases production and secretion of steroid hormones from the adrenal cortex
Adrenocorticotropic hormone (ACTH)
- essential for preparing mammary glands for lactation;
- after birth it is required for production of milk
- acts directly on its target tissues rather than through other hormones
Prolactin
formation of new blood vessels
angiogenesis
Growth hormone is also called as
somatotropin
- performs a vital role in governing body growth through its stimulatory effect on cellular mitosis, on synthesis of messenger RNA and protein, and on metabolism, especially in new tissue of young vertebrates
- acts directly on growth and metabolism, as well as indirectly through a polypeptide hormone produced by the liver
Growth hormone (somatotropin)
Insulin-like growth factor (IGF) is formerly called as
somatomedin
- formerly called somatomedin
- any of several peptide hormones that function primarily to stimulate growth but that also possess some ability to decrease blood glucose levels
Insulin-like growth factor (IGF)
- only anterior pituitary hormone produced by the intermediate lobe (except in birds and mammals)
- promotes dispersion of
the pigment melanin within melanocytes
Melanocyte-stimulating hormone (MSH)
source of two hormones of the posterior lobe of the pituitary
hypothalamus
Two hormones the posterior pituitary store and release
- Oxytocin
- Vasopressin
- two posterior-lobe hormones of mammals and are chemically very much alike
- Both are polypeptides consisting of eight amino acids (octapeptides)
- among the fastest-acting hormones, since they are capable of producing a response within seconds of their release from the posterior lobe
Oxytocin and Vasopressin
- stimulates contraction of uterine smooth muscles during parturition (birth of young)
- stimulates milk ejection by the mammary glands in response to suckling
Oxytocin
- acts on collecting ducts of the kidney to increase water reabsorption
- restrict urine flow
Vasopressin
Vasopressin is often called as
antidiuretic hormone (ADH)
increases blood pressure through its generalized constrictor effect on smooth muscles of arterioles
Vasopressin
increase thirst and drinking behavior
Vasopressin
- has the widest phylogenetic distribution
- considered the parent hormone from which other octapeptides evolved
Vasotocin
- occurs in all vertebrate except mammals
- water-balance hormone in amphibians
Vasotocin
Chemical nature of thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH)
glycoprotein
Hypothalamic controls of thyroid-stimulating hormone (TSH)
TSH-releasing hormone (TRH)
Hypothalamic controls of follicle-stimulating hormone (FSH)
Gonadotropin-releasing hormone (GnRH)1
Hypothalamic controls of luteinizing hormone (LH)
- Gonadotropin-releasing hormone (GnRH)1
- Gonadotropin release-inhibiting hormone (GnIH)2
Chemical Nature of prolactin (PRL)
protein
Hypothalamic controls of prolactin (PRL)
- dopamine (prolactin release-inhibiting hormone or PIH)
- prolactin-releasing factor (PRF)?
Chemical Nature of growth hormone (GH) (somatotropin)
protein
Hypothalamic controls of growth hormone (GH) (somatotropin)
- growth hormone-releasing hormone (GHRH)
- growth hormone release-inhibiting hormone (GHIH) or somatostatin
Chemical nature of adrenocorticotropic hormone (ACTH)
polypeptide
Hypothalamic controls of adrenocorticotropic hormone (ACTH)
corticotropin-releasing hormone (CRH)
Chemical nature of melanocyte-stimulating hormone (MSH)
polypeptide
Hypothalamic controls of melanocyte-stimulating hormone (MSH)
melanocyte-stimulating hormone-inhibiting hormone (MSHIH)
Chemical nature of oxytocin, vasopressin, and vasotocin
octapeptide
- produces hormone melatonin
- in nonmammalian, is responsible for circadian rhythms
pineal gland
- strongly affected by exposure to light
- production is lowest during daylight and highest at night
Melatonin secretion
- self-generated (endogenous) rhythms that are about 24 hours in length
- serves as biological clock for many physiological processes that follow a regular pattern
circadian rhythms
saclike evagination which lies just beneath the skull in a midline position
pineal complex
non-visual, photosensitive parapineal organ found in most lizards, frogs, the tuatara, and some species of fish
parietal eye
primary circadian pacemaker in mammals found in an area of the hypothalamus
suprachiasmatic nucleus
regulates the seasonal rhythms in reproduction in birds and mammals
photoperiod
plays a critical role in timing gonadal activity
melatonin
(animals) increasing melatonin secretion, reproductive activity suppressed during winter months
- horses
- ferrets
- hamsters
- deer mice
(animals) increasing melatonin levels, increased reproductive activity
- white-tailed deer
- silver fox
- spotted skunk
- sheep
modulate the activity of co-released neurotransmitters to either increase or decrease the strength of synaptic signaling
brain neuropeptides
can function similar to peptide hormones and modulate nearly all bodily functions
periphery neuropeptides
Examples of neuropeptides
- vasopressin
- gastrin and cholecystokinin
- endorphins and enkephalins
has been observed to enhance learning and improve memory when injected to people and experimental animals in minute quantities
vasopressin
structurally and functionally related peptide hormones that function as hormonal regulators of various digestive processes and feeding behaviors
Gastrin and cholecystokinin
- peptide hormone primarily responsible for enhancing gastric mucosal growth, gastric motility, and secretion of hydrochloric acid (HCl) into the stomach
- present in G cells of the gastric antrum and duodenum
Gastrin
- When fats and proteins enter your small intestine, it triggers your gallbladder and pancreas to contract
- function in control of feeding and satiety and may serve other functions as a brain neuroregulator
cholecystokinin
- neuropeptides that bind with opiate receptors and influence perception of pleasure and pain
endorphins and enkephalins
- hormones your body releases when it feels pain or stress
- released during pleasurable activities such as exercise, massage, eating and sex too
- help relieve pain, reduce stress and improve your sense of well-being
Endorphins
- naturally occurring peptide that has potent painkilling effects
- released by neurons in the central nervous system and by cells in the adrenal medulla
Enkephalin
- group of lipids with hormone-like actions that your body makes primarily at sites of tissue damage or infection
Prostaglandins
What causes dysmenorrhea during menstruation?
overproduction of uterine prostaglandins
regulate vasodilation or vasoconstriction by their action on smooth muscle in walls of blood vessels in some tissues
prostaglandins
known to stimulate contraction of uterine smooth muscle during childbirth
prostaglandins
small proteins that are crucial in controlling the growth and activity of other immune system cells and blood cells
Cytokines
Most important hormones of metabolism are those of the:
- Thyroid
- Parathyroid
- Adrenal glands
- Pancreas
- Growth hormone of the anterior pituitary
- White adipose tissue
large endocrine gland located in the neck of all vertebrates
thyroid gland
structural and functional units of a thyroid gland
thyroid follicles
hormones that the thyroid gland synthesize, store and release
- Triiodothyronine (T3)
- Thyroxine (T4)
- Calcitonin
hormones play an important role in regulation of your weight, energy levels, internal temperature, skin, hair, nail growth, metabolism
- triiodothyronine (T3)
- thyroxine (T4)
thyroid gland makes and releases to help regulate calcium levels in your blood by decreasing it
Calcitonin
Important function of the thyroid gland
promote adaptation to cold environments by increasing heat production
- stimulate cells to produce more heat and store less chemical energy (ATP)
- reduce efficiency of cellular oxidative phosphorylation
thyroid hormones
an element that is needed for the production of thyroid hormone
Iodine
What is combined with iodine to make the two thyroid hormones
amino acid tyrosine
characterized by an excess of thyroxine in the bloodstream
Thyrotoxicosis
Thyrotoxicosis can be caused by
hyperthyroidism
overactivity of the thyroid gland
hyperthyroidism
Role of thyroid hormones in birds and animals
- control of oxygen consumption
- heat production
Oversecretion of thyroid hormones accelerates body processes by as much as __
50%
Hyperthyroidism symptoms
- irritability
- nervousness
- fast heart rate
- intolerance to warm environments
- loss of body weight despite increased appetite
Hypothyroidism symptoms
- loss of mental alertness
- slowing of heart rate
- muscular weakness
- increased sensitivity to cold
- weight gain
irregular growth of the thyroid gland
goiter
- these tiny glands occur as two pairs in humans but vary in number and position in other vertebrates
- helps maintain the right balance of calcium in the bloodstream and in tissues that depend on calcium for proper functioning
parathyroid glands
Decrease in calcium leads to serious increase in:
- nervous-system excitability
- severe muscular spasms
- tetany
- death
What do parathyroid glands secrete that is essential to maintain calcium homeostasis
parathyroid hormone (PTH)
synthesize organic fibers and glycoproteins of bone matrix which later become mineralized with a form of calcium phosphate called hydroxyapatite
osteoblasts
giant cells that dissolve the bony matrix, releasing calcium and phosphate into the blood
osteoclasts
increase stimulates osteoclasts to dissolve bone adjacent to these cells, thus releasing calcium and phosphate into the bloodstream and returning blood calcium level to normal
parathyroid hormone
essential for active calcium absorption by the gut
1,25- dihydroxyvitamin D3
- released in response to elevated levels of calcium in the blood
- rapidly suppresses calcium withdrawal from bone, decreases intestinal absorption of calcium
- increases excretion of calcium by the kidneys
calcitonin
protects body against an increase in level of calcium in the blood
calcitonin
protects body from a decrease in blood calcium
parathyroid hormone
outer region and also the largest part of an adrenal gland
adrenal cortex
class of steroid hormones released by the adrenal cortex, which includes glucocorticoids and mineralocorticoids
Corticosteroids
Two classifications of corticosteroid hormones
- glucocorticoids
- mineralocorticoids
- concerned with food metabolism, inflammation, and stress
- promote synthesis of glucose from compounds other than carbohydrates, particularly amino acids and fats
glucocorticoids
Ex. of glucocorticoids
- cortisol
- corticosterone
increases blood glucose levels via the stimulation of gluconeogenesis and through antagonism of insulin
Cortisol
refers to synthesis of new glucose from noncarbohydrate precursors, provides glucose when dietary intake is insufficient or absent
Gluconeogenesis
the second group of corticosteroids, are those that regulate salt balance
Mineralocorticoids
- promotes tubular reabsorption of sodium and tubular secretion of potassium by the kidneys
- the most important steroid of this group
Aldosterone
also produces androgens
Adrenocortical tissue
promote some developmental changes, such as the growth spurt, that occur just before puberty in human males and females
Adrenal androgens
- inner part of the adrenal gland (a small organ on top of each kidney)
- makes chemicals such as epinephrine (adrenaline) and norepinephrine (noradrenaline) which are involved in sending nerve signals
adrenal medulla
What does the adrenal medulla secrete?
- epinephrine (adrenaline)
- norepinephrine (noradrenaline)
epinephrine
adrenaline
norepinephrine
noradrenaline
- help you prepare for stressful or dangerous situations
- gets your body ready for a “fight or flight” response
- has slightly more of an effect on your heart
Epinephrine (adrenaline)
quick release of adrenaline into your bloodstream
Adrenaline rush
- increases heart rate and blood pumping from the heart
- increases blood pressure and helps break down fat and increase blood sugar levels to provide more energy to the body
- has more of an effect on your blood vessels
norepinephrine
have effects that center on responses to emergencies, such as fear and strong emotional states, flight from danger, fighting, lack of oxygen, blood loss, and exposure to pain
adrenal medullary hormones
Effects of epinephrine and norepinephrine
- constriction of arterioles
- mobilization of liver glycogen and fat stores to release glucose and fatty acids for energy
- increase oxygen consumption & heat production
- hastening of blood coagulation
- inhibition of gastrointestinal tract
both an exocrine and an endocrine organ
pancreas
produces pancreatic juice, a mixture of digestive enzymes and bicarbonate ions conveyed by a duct (or ducts) to the digestive tract
pancreas (exocrine)
- groups of pancreatic cells secreting insulin and glucagon
- numerous small islets of tissue scattered within the extensive exocrine portion of the pancreas
Islets of Langerhans
Three polypeptide hormones that are secreted by different cell types within the islets
- Insulin
- Glucagon
- Pancreatic polypeptide
Endocrine cells
- alpha cell
- beta cell
produce and transport chemicals that will exit the body through the digestive system
exocrine cells (acinar cells)
Insulin is produced by what cells
beta cells
Glucagon is produced by what cells
alpha cells
- essential for uptake of blood-borne glucose by cells, especially skeletal muscle cells
- promotes entry of glucose into body cells through its action on a glucose transporter molecule found in cell membranes
- important in central regulation of food intake and body weight
insulin
condition in which level of glucose in the blood rises to abnormally high levels without insulin
hyperglycemia
condition in which your blood sugar (glucose) level is lower than the standard range
hypoglycemia
- disease of insulin deficiency
- If left untreated, it can lead to severe damage to kidneys, eyes, and blood vessels, and it can greatly shorten life expectancy
diabetes mellitus type 1
- disease of insulin insensitivity
- This disease is occurring at an increasing rate as more individuals become overweight and obese
diabetes mellitus type 2
raises the blood-glucose level (by converting liver glycogen to glucose)
glucagon
lowers blood glucose
insulin
- newest pancreatic hormone
- released after a meal and reduces appetite
Pancreatic polypeptide (PP)
- acts directly on long bones to promote cartilaginous growth and bone formation
- acts indirectly on growth via stimulation of insulin-like growth factor (IGF)
- important metabolic hormone in young animals during growth and development
Growth hormone (GH)
promotes mobilization of glycogen from liver stores and release of fat from adipose tissue stores necessary for growth processes
- insulin-like growth factor (IGF) or
- somatomedin
Growth hormone is considered to be a __ hormone
diabetogenic
excess production of growth hormone
gigantism
growth hormone deficiency
dwarfism
- regulates eating behavior and long-term energy balance as part of a feedback system that informs the brain, particularly the hypothalamus and brain stem, of the energy status of the periphery
- become immensely significant in the study of satiety signals and energy expenditure, since these studies relate to the overall problem of human obesity
leptin
tends to lower blood glucose levels by increasing the effects of insulin on liver and skeletal muscle
Adiponectin
- inflammatory cytokine produced by macrophages/monocytes during acute inflammation
- responsible for a diverse range of signaling events within cells, leading to necrosis or apoptosis
- important for resistance to infection and cancers
- high levels are associated with obesity-related insulin insensitivity
Tumour Necrosis Factor alpha (TNF alpha)
Four (4) major digestive hormones
- Gastrin
- Secretin
- Cholecystokinin
- Glucose-dependent insulinotropic peptide (GIP)
- Promotes the secretion of gastric juice (HCl, mucus, pepsinogen)
- Increases gastric motility
- Pyloric sphincter relaxation
gastrin
stimuli of gastrin
- stomach expansion
- protein & caffeine in stomach
- alkaline chyme in stomach
secretion site of gastrin
Enteroendocrine cells of stomach mucosa
Stimulates pancreatic enzyme secretions into the duodenum via the sphincter of Oddi
secretin
What are the pancreatic secretions that secretin stimulates
bicarbonate-rich, neutralize acidic chyme
stimuli of secretin
acidic chyme in duodenum
secretion site of secretin
enteroendocrine cells of duodenum
- Increases bile secretion from the gallbladder.
- Promotes pancreatic enzyme secretion
- Promotes relaxation of the sphincter of Oddi.
cholecystokinin (CKK)
stimulus of cholecystokinin
- triglycerides
- fatty acids
- amino acids (part of chyme)
in duodenum
secretion site of cholecystokinin
enteroendocrine cells of duodenum
- Promotes pancreatic insulin secretion
- Prevents stomach acid secretion
Glucose-dependent insulinotropic peptide (GIP)
stimulus of glucose-dependent insulinotropic peptide (GIP)
- glucose
- fatty acids & amino acids; all present in chyme
in duodenum
secretion site of glucose-dependent insulinotropic peptide (GIP)
enteroendocrine cells of duodenum
What glands regulate the reproductive system
- pituitary gland
- adrenal cortex
- gonads
Hormone that is released during puberty of males and females
gonadotropin-releasing hormone (GnRH)
Gonadotropin-releasing hormone (GnRH) stimulates the production and release of what hormones?
- follicle-stimulating hormone (FSH)
- luteinizing hormone (LH)
stimulates gamete production in both males and females
follicle-stimulating hormone (FSH)
stimulates gonad hormone production
luteinizing hormone (LH)
- protein secreted by the Sertoli cells in men and by the granulosa cells in women
- inhibits the synthesis and release of the follicle-stimulating hormone in the pituitary gland and reduces the hypothalamic LH - releasing hormone content
Inhibin
most well knwon androgen in males
testosterone
In men,
regulate sex drive (libido), bone mass, fat distribution, muscle mass and strength, and production of red blood cells and sperm
testosterone
Luteinizing hormone (LH) stimulates the production of what hormones in the ovaries
- estradiol
- progesterone
- steroid hormones that assist the body in preparing for pregnancy
- regulate menstrual cycle
estradiol & progesterone
responsible for the development of secondary sexual characteristics or bodily features that appear during puberty
Estradiol
stimulates production of milk by the mammary glands following childbirth
prolactin
prolactin are regulated by what hypothalamic hormones
- prolactin-releasing hormone (PRH)
- prolactin-inhibiting hormone (PIH)
stimulates release of prolactin
prolactin-releasing hormone (PRH)
inhibits release of prolactin
prolactin-inhibiting hormone (PIH)
- reflex that makes breastmilk flow
- When the baby sucks at the breast, tiny nerves are stimulated. This causes two hormones – prolactin and oxytocin – to be released into your bloodstream. Prolactin helps make the milk, while oxytocin causes the breast to push out the milk
let-down reflex
Two factors where the concentration of hormone in body fluid depends
- rate of secretion
- rate at which it is inactivated and removed from circulation
- operate between glands secreting hormones and outputs or products of target cells
- highly effective in preventing extreme oscillation in hormonal output
negative feedback
- the signal (or output of the system) feeds back to the control system and causes an increase in the initial signal
- initial signal becomes progressively amplified to produce an explosive event
- highly regulated and possess an obvious shutoff mechanism
positive feedback
growth of tissue cells
Proliferation
produces the hormone progesterone that makes your uterus a healthy environment for a developing fetus
corpus luteum