Endocrine System Flashcards
How do the endocrine and nervous system interact?
The hypothalamus (nervous) sends neurotransmitters to the pituitary gland (endocrine) which can stimulate other endocrine glands to secrete hormones.
What is an endocrine gland?
They are ductless glands that secrete their hormones directly into the blood stream.
What are hormones?
They control the internal environment of the body from the cellular level
What are the three different types of hormones?
Modified amino acids
Protein
Steroid
Give an example of an amino acid hormone and where it is produced.
Adrenal medulla: epinephrine, norepinephrine.
Posterior pituitary: oxytocin & vasopressin.
Give an example of a protein hormone and where it is produced.
Anterior pituitary gland: gonad stimulating hormone, growth hormone.
Pancreatic islets: insulin
Give examples of steroid hormones and where they are produced.
Adrenal cortex: cortisol
Gonads: estrogen & testosterone.
What is the difference between amino acid, protein and steroid hormones bind?
Amino acid & protein hormones bind to the membrane-bound receptors sites on the cells of target organs. Where as a steroid hormone are soluble in lipids and therefore can cross the cell membrane and binds inside the cell
How do the hypothalamus and the pituitary link?
Via a funnel-shaped stalk called infundibulum.
What kind of chemical signals does the hypothalamus give to the pituitary?
It sends releasing hormones and releasing inhibitory hormones.
These stimulate or inhibit the release of particular hormones in the pituitary.
What are the endocrine glands?
Pituitary gland, pineal gland, thyroid gland, parathyroid gland, thymus, adrenal, islets of Langerhans of the pancreases, ovaries, testes
What is another name for the pituitary gland?
Hypophysis
What is another name for anterior/posterior pituitary?
Anterior =adenohypophysis
Posterior= neurohypophysis
Where is GH (Growth hormone) produced and what does it do?
GH is produced by the anterior pituitary lobe. It stimulates cell metabolism causes cells to divide and increase in size. It also increases protein synthesis, breakdown of fats and carbohydrates, stimulates growth of bone and muscle.
What happens if you don’t have enough GH when your growing?
Cause pituitary dwarfism. The person remains small but body portions are normal.
What happens if a person has to much GH?
In childhood can result in Gigantism.
If after childhood when bone has stopped growing results in acromegaly. Bones widen especially in the face, hands and feet.
What does TSH (thyroid stimulating hormone) do?
It stimulates the thyroid.
What regulates TSH (thyroid-stimulating hormone)
Hypothalamus (produces thyrotropin-releasing hormone (TRH) which stimulates the terror pituitary lobe to secrete TSH)
What does adrenocorticotrophic hormone (ACTH) stimulate?
It’s stimulates the adrenal cortex to secrete its hormone called cortisol.
What regulates Adrenocorticotropic (ACTH)
ACTH is regulated by corticotropin-releasing hormone (CRH) produced by the hypothalamus.
What is ACTH involved with?
ACTH is involved with the glucose-sparing effect and helps reduce inflammation as well as stimulating the adrenal cortex.
What does Melanocytes-stimulating hormone (MSH) do?
It increases the production of melanin in melanocytes in the skin, thus causing a deepening pigmentation/darkening of the skin.
What stimulates the ovaries in females to develope follicles?
Follicle-stimulating hormone.
What does FSH stimulate in males
Sperm production in the seminiferous tubules of the testes
What does Luteinizing hormone (LH) do?
It stimulates ovulation in the female ovary and production of the female sex hormone progesterone. It also helps maintain pregnancy.
What does LH do in males?
Stimulates the synthesis of testosterone in the testes to maintain sperm cell production.
What is another name for Lactogenic hormone (LTH)
Prolactin
What does LTH/prolactin do?
It stimulates milk production in the mammary glands following delivery in pregnant females.
It also helps to maintain progesterone levels following ovulation and during pregnancy.
What does Lactogenic hormone do in males?
It increases sensitivity to LH and may cause a decrease in male sex hormones
What is the posterior pituitary lobe composed of?
Nerve fibres and neuroglia cells that support the nerve fibres.
What is the anterior lobe of the pituitary made up of?
Glandular epithelial cells
What is another name for vasopressin?
Antidiuretic hormone (ADH)
What does ADH do?
Maintains the body’s water balance by promoting increase water reabsorption in the tubules of the nephrons of kidneys resulting in less water in the urine.
What happens if someone has a deficiency in ADH?
A condition called: diabetes insipidus. They produce 20-30L of urine daily.
What does oxytocin do?
OT stimulates contractions of smooth muscles in the wall of the uterus.
What stimulates OT?
Stretching of uterine and vaginal tissues in late pregnancy stimulates production of OT so that uterine contractions develop in the late stages of childbirth.
What else does oxytocin (OT)do?
It also causes contraction of cells in the mammary glands causing milk ejection or lactation forcing the milk from the glandular ducts into the nipple during breastfeeding.
Why would a women be given OT?
1) help to induce labor
2) give to women after childbirth to constrict blood vessels of the uterus to minimize the risk of hemorrhage.
Describe how the thyroid is made
It consist of two lobes connected by a smaller band called the isthmus. The loves are situated on the right and left sides of the trachea and thyroid cartilage just below the larynx
What covers the thyroid gland?
Covered with a capsule of connective tissue. It is made up of spheres of cells called follicles.
What are the follicles on the thyroid gland composed of?
They are composed of cuboidal epithelium. Which produces and secretes the thyroid horomones.
How is the thyroid gland regulated?
The hypothalamus signals the pituitary to release TSH to increase thyroid production.
What does the thyroid require to work properly?
Iodine
What happens if you don’t have enough iodine in you body?
The thyroid gland can enlarge to form a goiter.
What is another name for thyroxine?
Tetraiodothyronie
What does tetraiodothyronie (thyroxine) abbreviated to and why?
T4 b/c it contains four iodine atoms
What is the abbreviation for triiodothyronine?
Contains 3 iodine atoms = T3
What do T4 & T3 do?
They regulate the metabolism of carbohydrates, fats, proteins. They are necessary for normal growth and development and maturation of the nervous system.
What happens if you have low or lack thyroid hormones?
Hypothyroidism.
What happens in children if they are hypothyroidism?
They can develop a condition known as cretinism. = mentally retarded and does not grow to normal stature.
What happens in adults who are hypothyroid?
Lower metabolism, causing sluggishness, to tired to perform normal daily tasks.
What can accumulate in adults who are hypothyroid.
Can have an accumulation of fluid in subcutaneous tissues called myxedema
What is it called if you have to much thyroid hormone?
Hyperthyroidism. = extreme nervousness, fatigue, increased rate of body metabolism.
What is Graves’ disease?
A type of hyperthyroidism caused by overproduction of thyroid production. Associated with enlarged thyroid gland/goiter and bulging of eyeballs (exophthalmia)
What is exophthalmia?
Bulging of the eyeballs associated with Graves’ disease.
Where is calcitonin excreted from?
The extrafolliclar cells of the thyroid.
What does calcitonin do?
Lowers calcium/phosphate ion in blood by inhibiting it being released from bones and by increasing excretion of these ions by the kidneys.
What is thyroid secretion controlled by?
THS produced by the anterior pituitary gland
How is the thyroid regulated?
By an negative feedback loop that inhibits the anterior pituitary gland from releasing more TSH and the hypothalamus from secreting TSH releasing hormone.
Where are the parathyroid glands found?
The four glands are embedded in the posterior surface of the thyroid gland.
What are the parathyroid glands made up of?
Chief cells and oxyphil cells which are close to capillary network.
What hormone does parathyroid secrete?
Parathyroid hormone (also called parathormone (PTH) inhibits the activity of osteoblasts and causes osteoclasts to break down matrix issues.
What does parathormone do?
PTH inhibits the activity of osteoblasts and causes osteoclasts to break down bone matrix tissue releasing Ca and phosphate ions into the blood.
How does PTH affect kidneys?
Parathormone causes kidneys to conserve Ca and stimulates intestinal cells to absorb Ca from digested food in the intestine.
What is hyperparathroidism?
An abnormally high level of PTH secretion. Can be caused by a tumour. It causes bones to become soft and brittle. The elevated Ca levels in the blood cause muscles and nerves to become less excitable resulting in muscle weakness and fatigue. Access Ca and phosphate ions may become deposited in kidneys resulting in kidney stones
What happens if you are hypoparathyroidism?
(Caused by surgical removal or injury). Decreased osteoclast activity. Bones remain strong but decreased blood Ca results in nerves and muscles becoming abnormally excitable producing spontaneous action potentials. Causing frequent muscle cramps or gentamicin contractions. If affecting respiratory muscles breathing failure and death can occur.
What is another name for adrenal glands?
Suprarenal glands
Where are the adrenal/suprarenal glands found?
On top of each kidney
What is the inside/outside of the suprarenal called.
Inside: adrenal medulla
Outside: adrenal cortex
What does the adrenal medulla produce?
Adrenaline (epinephrine)and small amounts of norepinephrine (noradrenaline)
What causes the release of epinephrine and norepinephrine?
The are released in responses from the the sympathetic division of the autonomic nervous system via hypothalamus
What do epinephrine and norepinephrine do?
They breakdown of glycogen in the liver to glucose and the release of fatty acids stored fat cells. They are released into the blood stream as a quick sources of ATP. They also increase HR, BP to get glucose and fatty acids to the muscle cells.
How is the adrenal cortex made up?
Of three densely packed layers of epithelial cells forming an inner, middle, outer region of the cortex
What group of hormones does the outer layer of the adrenal cortex called? What do they do?
Mineralcorticoid = regulate the concentration of mineral electrolytes.
What is an example of a mineralocorticoid hormone and what does it do?
Aldosterone = regulates Na reabsorption and potassium excretion by the kidneys.
What does the middle layer of the adrenal cortex excrete? What does it do?
Cortisol (hydrocortisone a glucocorticoid hormone)= stimulates the liver to synthesize glucose from circulating amino acids and cause adipose tissue to break down into fatty acids. These are released into the blood as a quick source of energy.
What is cortisone?
Steroid closely related to cortisol given to help reduce inflammation. (Helps with arthritic joints)
What does the inner adrenal cortex produce and what does it do?
Produces sex hormones called androgens. ->in men help to stimulate development of male sexual characteristics. (Women= female sex drive)
What is Addison’s disease?
Caused by the adrenal cortex failing to produce enough hormones.
= decreased Na, low levels of blood glucose causing fatigue, dehydration. Without treatment can lead to death due to severe changes in electrolyte balance in the blood.
What is Cushing’s syndrome.
When there is to much secretion from the adrenal cortex. Blood glucose remains to high lowering tissue protein. Retention of Na causes fluid increase resulting in puffy skin. Can cause mental problem in women. Can also causes changes in women such as facial hair growth, lowering pitch of voice
Where is insulin and glucagon produced?
Pancreatic islets (islets of Langerhans)
Where does the pancreatic duct connect to?
The duodenum of the small intestine. It helps to transport digestive juices to the intestine.
What do alpha and beta cells secrete and where are they found ?
They are found on the islets of Langerhans.
Alpha = glucagon
Beta= insulin
What happens after you eat?
Your blood glucose spikes so the beta cells release insulin. Insulin promotes the glucose in the blood to be transformed in the liver into glycogen. (Animal starch) Glucose is also moved into muscle cells and adipose tissue.
What happens when glucose in the blood decreases
The pancreatic islets secrete the hormone glucagon. Glucagon stimulates the lover to convert stored glycogen into glucose. Glucagon also causes the breakdown of aa and their conversation to raise blood sugar levels.
What is acidosis?
A decline in blood glucose causing nervous system malfunction.
What happens is blood glucose is to high?
Kidneys produce lg volumes of urine leading to dehydration
What does testosterone do?
Development of male reproduction structures, development of secondary male characteristics, sex drive and aggression.
What do estrogen and progesterone do?
They promote development of female reproduction structures, secondary female characteristics, controls menstrual cycle.
What does the thymus do?
Secretes thymosin = causes production of T lymphocytes.
What does the pineal gland/body produce?
Melatonin which is searched directly into the cerebrospinal fluid.
Melatonin inhibits the secretion fo the gonadotropin hormones LH and LSH thus inhibiting reproductive system.
It also affects our sleep-wake patterns. Melatonin production is inhibited by light
Where is serotonin secreted?
By the pineal gland. It acts as a neurotransmitter and a vasoconstrictor. Stimulates smooth muscle contraction and inhibits gastric secretions
Which hormones are modified amino acids?
Epinephrine, norepinephrine, oxytocin, vasopressin (ADH)
Which hormones are proteins?
Insulin & growth hormone.
Which hormones are steroids?
Cortisol, estrogen, testosterone
The gland crucial to the immune system is the
Thymus
The gland responsible for secretion of melatonin is the
Pineal
The gland that secretes cortisol is the
Adrenal
The secretion that regulates the blood sugar level is
Glucagon
A low blood sugar level can result in
Acidosis
Epinephrine is secreted by
Adrenal cortex
Vitamin D increase the absorption rates of
Ca
What gland(s) need iodine to function properly
The thyroid. Without iodine can lead to a goiter
ADH helps maintain proper water balance in the body. It is also called
Vasopressin
The hormone that stimulates ovary follicle development and sperm production is
FSH= follicle stimulating hormone
The master gland is controlled by the
Hypothalamus
The hormone that can diffuse across cell membranes are the
Steroids
Production of T lymphocytes is done in the
Thymus
Glycogen is stored for use between meals. It is stored in which organ?
Liver
The functions of the reproductive system are inhibited by
Melatonin
The pineal gland secretes which two substances?
Melatonin/serotonin
Polyuria, polydipsia, polyphagia are associated with
Diabetes
If blood glucose decreases excessively, fatty acids and what are released to causes acidosis?
Ketones
Pancreatic juice is produced by
Acini cells
Insulin is produced by the
Beta cells within the pancreases
Glucagon is produced by the
Alpha cells
Androgens are produced by
Adrenal cortex
Overproduction of hormones by the adrenal cortex can lead to
Cushing syndrome: blood glucose concentrations remain high, retention of Na = puffiness and obesity. also increase in adrenal male sex hormones in females= masculinity changes in women= facial hair growth, lowering pitch of voice
A bronzing of the skin is a symptom of which disease?
Addison’s
The gland sitting on top of kidney is the
Adrenal
What hormones are secreted by the thyroid gland?
- calcitonin: lowers Ca and Phosphate in blood by inhibiting the release from bones and by increasing the exceptions of these ions in the kidney
- thyroxine (tetraiodothyronie)
- triiodothyronine
What hormone stimulates milk production
Lactogenic hormone (LTH)/prolactin
What hormone stimulates the thyroid gland to produce its own hormone
TSH
What makes up the bulk of the adrenal gland?
Adrenal cortex
Thymosin causes the production of
White blood cells
What is a proprioceptor?
A sensory receptor which receives stimuli from within the body, especially one that responds to position and movement.
What is a baroreceptor?
A receptor sensitive to pressure
What is a osmoreceptor?
Detects osmotic pressure
What is a nocieptor?
a sensory receptor for painful stimuli
Where are the mengies located?
Surrounds the brain and spinal cord.
What is the mengies function?
Protect the brain and spinal cord
Where is the spinal cord?
Centre of the back enclosed within the vertebrae
Where is the Cerebral spinal fluid located?
Between the arachnoid and pia mater
What is the structure of Cerebral spinal fluid?
A clear watery circulating fluid
What is the function of the cerebral spinal fluid?
Protection of the brain and spinal cord
Where is the cerebrum located?
Makes up the bulk of the brain.
What is the cerebrum composed of?
Grey matter= cerebral cortex
White mater
Separated into hemispheres by longitudinal fissures.
Four lobes: frontal, partial, temporal, occipital
Describe the 4 different lobes functions:
Frontal: mood, aggression, motivation, voluntary muscle control, smell
Parietal: evaluating sensory information for temp, taste, pain, balance,
Temporal: involved in memory process, judgment and abstract thought, evaluates smells and hearing
Occipital: interpreting visual input
Where is the cerebellum located?
2nd largest portion, underneath the occipital lobe and behind the pons and the medulla oblongata
What is the cerebellum composed of?
Primarily white matter and with thin cover of grey matter.
What is the cerebellum function
Coordinating skeletal muscle movement, maintaining posture and balance
What are the main structures in the diencephalon?
Thalamus and hypothalamus
Also contains: optic tracts, optic chasm, infundibulum, epithalamus and pineal gland.
What does the Thalamus do?
Relay station for impulses that reach the cerebral cortex from the spinal cord.
What does the epithalamus do?
Concerned with emotional and visceral responses to odor
What does the hypothalamus do?
Controls and integrates ANS.Works along side the endocrine system via the pituitary gland. Controls feelings of rage/aggression.
What is the brain stem composed of?
Medulla oblongata
Pons varolii and midbrain
What does the medulla oblongata do?
Part of brain stem: contains acending and descending tracts that connect to the spinal cord
What do the pons varolii do?
Part of the brain stem: the pons connect the spinal cord with the brain and the brain with other part of the brain. Acts as a bridge
What does the midbrain do?
Part of the brainstem: the midbrain (also called Mesenephalon) coveys impulses from the cerebral cortex to the pons and spinal cord. Contains reflex center that controls the movement of eyes and head in response to visual stimuli
Moves head and truck in response to auditory stimuli
