Exam 3 Flashcards
The endocrine system controls body activities by…
releasing hormones.
Hormones help regulate…
- extracellular fluid
- metabolism
- contraction of cardiac & smooth muscle
- glandular secretion
- some immune functions
- growth and development
- reproduction
Which glands have primary function as an endocrine gland?
- Pituitary gland
- thyroid gland
- parathyroid gland
- adrenal gland
- pineal gland
What has secondary function as an endocrine gland?
- hypothalamus
- thymus
- pancreas
- ovaries
- testes
- kidneys
- stomach
- liver
- small intestine
- skin
- heart
- placenta
- adipose tissue
Although hormones travel throughout the body…
they only affect specific target cells (with specific protein or glycoprotein receptors)
What are endocrines?
Hormones that travel in the blood and act on distant target cells.
What are local hormones?
Hormones that act locally without entering the bloodstream.
What are the 2 types of local hormones?
Paracrines & Autocrines
Paracrines act on…
neighboring cells
Autocrines act on…
themselves (the cells that secreted them)
What types of hormones are lipid soluble?
- Steroids
- Thyroid hormones
- nitric oxide
What are the 3 groups of water soluble hormones?
- Amines
- Peptides, proteins, and glycoproteins
- Eicosanoids
What hormones are amines?
- epinephrine
- norepinephrine
- melatonin
- seratonin
What hormones fall in the group of peptides, proteins and glycoproteins?
- insulin
- growth hormone
- ADH
What hormones are eicosanoids?
- prostaglandins
- leukotrienes
Lipid soluble hormones bind to and activate receptors…
within the cell (not on the surface)
Receptors activated by lipid soluble proteins…
alter gene expression resulting in formation of new proteins.
Water soluble hormones alter cell functions by …
activating plasma membrane receptors, setting of a cascade of events inside the cell.
The cascade of events initiated by a water soluble hormone is called…
the messenger system
What is the first messenger in the messenger system?
The hormone that binds to the cell membrane receptor.
What is the second messenger in the messenger system?
A chemical activated inside the target cell.
What is a common second messenger?
Cyclic AMP (cAMP)
Which hormones increase cAMP levels?
ADH, TSH, ACTH, glucagon, & epinephrine
Which hormones decrease cAMP levels?
growth hormone inhibiting hormone (somatostatin)
What substances can act as second messengers?
- cAMP
- calcium ions
- cGMP
- PI3
- Tyrosine Kinase
What is the major integrating link between the nervous and endocrine systems?
Hypothalamus
The hypothalamus receives input from…
cortex, thalamus, limbic system, & internal organs
What does the hypothalamus control with releasing and inhibiting hormones?
Pituitary gland
What are the hormones of the anterior pituitary gland?
- Human growth hormone (hGH)
- Thyroid-stimulating hormone (TSH)
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Prolactin (PRL)
- Adrenocorticotrophic hormone (ACTH)
- Melanocyte-stimulating hormone (MSH)
Hormones stored and released by the posterior pituitary gland are made in the…
Hypothalamus
What 2 hormones are released by the posterior pituitary gland?
- Oxytocin (OT)
- antidiuretic hormone (ADH)
What is the most plentiful hormone of the anterior pituitary gland?
hGH
What cells does hGH target?
- liver cells
- skeletal muscle cells
- cartilage cells
- bone cells
What is the function of hGH?
- increase cell growth and division
- increase cellular uptake of amino acids
- increase synthesis of proteins
- stimulate triglyceride breakdown
- slows down use of glucose for ATP production to keep blood glucose levels high enough to supply the brain
What promotes the release of hGH
growth hormone releasing hormone (GHRH, somatocrinin)
What inhibits the release of hGH?
growth hormone inhibiting hormone (GHIH, somatostatin)
What is the function of TSH?
stimulate synthesis and secretion of T3 and T4 by the thyroid gland.
What promotes the release of TSH?
thyrotropin releasing hormone (TRH)
What inhibits the release of TSH?
Somatostatin and negative feedback by elevated levels of T3 & T4.
What are the functions of FSH?
- initiates the formation of follicles within the ovaries
- stimulates follicle cells to secrete estrogen
- stimulates sperm production in testes.
What promotes the release of FSH
gonadotropin releasing hormone (GnRH)
What inhibits the release of FSH?
negative feedback by elevated levels of sex hormones.
What is the function of LH in females?
- stimulates secretion of estrogen
- stimulates ovulation of 2nd oocyte from ovary
- stimulates formation of corpus luteum
- stimulates secretion of progesterone
What is the function of LH in males?
-Stimulates secretion of testosterone.
What promotes the release of LH?
(GnRH)
What inhibits the release of LH?
Negative feedback by sex hormones.
What is the function of prolactin?
-initiate and maintain milk secretion by mammary glands.
What promotes the release of prolactin?
Prolactin releasing hormone (PRH)
What inhibits the release of prolactin?
prolactin inhibiting hormone (PIH, Dopamine)
What is the function of ACTH?
controls the production and secretion of gluccocorticoids (cortisol) by the cortex of the adrenal gland.
What promotes the release of ACTH?
corticotropin releasing hormone (CRH)
What inhibits the release of ACTH?
Negative feedback by elevated levels of gluccocorticoids,
What is the function of MSH?
- it’s role in humans is unknown.
- increases skin pigmentation in animals.
What promotes the release of MSH?
Corticotropin releasing hormone (CRH)
What inhibits the release of MSH
dopamine
What are the target tissues of Oxytocin?
- uterus
- breasts
What is the function of oxytocin?
- enhance uterine contraction during delivery
- promotes expulsion of placenta after delivery
- stimulates milk let down during breast feeding.
What promotes the release of ADH?
osmotic pressure of blood
What is secreted by thyroid follicles?
thyroid hormones, thyroxine(T4) and Triiodothyronine (T3)
what is secreted by parafollicular cells of the thyroid gland?
calcitonin (CT)
Thyroid hormones are synthesized by…
TGB (thyroglobulin)
Thyroid hormones are transported in the blood by
TBG (thyroxine-binding globulin)
What is the function of thyroid hormones?
- increase basal metabolic rate
- stimulate synthesis of Na+/K+ ATPase
- increase body temperature
- stimulate protein synthesis
- increase use of glucose and fatty acids for ATP production
- stimulate lipolysis
- enhance actions of some catecholamines
- regulate development and growth of nervous tissue and bones
What is the function of calcitonin?
- responsible for building of bone
- stops resorption of bone
- lowers blood levels of calcium
What are the cells of the parathyroid gland?
- principal cells
- oxyphil cells
What is produced by principal cells of the parathyroid gland?
Parathyroid hormone
What is the function of parathyroid hormone?
- increase blood calcium levels
- decrease blood phosphate levels
- increases the number and activity of osteoclasts
- increases the rate of Ca2+ and Mg2+ reabsorption from urine
- promotes secretion of HPO42-
- promotes formation of calcitriol, which increase absorption of calcium, magnesium, and phosphate from the GI tract.
The adrenal gland is made up of…
an outer cortex and inner medulla
What are the 3 zones in the cortex of the adrenal gland?
- Zona glomerulosa (outer zone)
- Zona fasciculata (middle zone)
- Zona reticularis (inner zone)
What hormones are secreted by the zona glomerulosa?
mineralocorticoids (aldosterone)
What hormones are secreted by the zona fasciculata?
gluccocorticoids (Cortisol)
what hormones are secreted by the zona reticularis?
androgens
what is the function of aldosterone?
- increase reabsorption of Na+
- promotes excretion of K+ and H+
What is the function of cortisol?
- increase rate of protein catabolism and lipolysis
- conversion of amino acids to glucose
- provide resistance to stress by making nutrients available for ATP production
- raise blood pressure by vasoconstriction
- anti-inflammatory
What is the function of androgens?
- insignificant in males
- may contribute to sex drive in females
- converted to estrogen in postmenopausal females
What hormones are produced by the medulla of the adrenal gland?
epinephrine and norepinephrine
What cells make up the pancreatic islets?
- Alpha cells
- Beta cells
- Delta cells
- F cells
What is produced by the alpha cells of the pancreatic islets?
glucagon
What is produced by the beta cells of the pancreatic islets?
insulin
What is produced by the delta cells of the pancreatic islets?
somatostatin
what is produced by the F cells of the pancreatic islets?
pancreatic polypeptide
What is the function of glucagon?
- raise blood glucose levels
- stimulate glycogenolysis
- stimulate gluconeogenesis
What is the function of insulin?
- lowers blood glucose levels
- accelerates facilitated diffusion of glucose into cells
- speeds up glycogenesis
- increases uptake of amino acids and increases protein synthesis
- speed lipogenesis
- slows glycogenolysis
- slows gluconeogenesis
What is the function of pancreatic polypeptide?
- inhibits secretion of somatostatin
- inhibits gall bladder contraction
- inhibits secretion of pancreatic digestive enzymes
What is found in the pineal gland?
melatonin
What are the hormones produced by the thymus gland?
- thymosin
- thymic humoral factor
- thymic factor
- thymopoietin
What is the function of prostaglandins?
- alter smooth muscle contractions
- alter glandular secretion
- alter blood flow
- alter platelet function
- alter nerve transmission
- alter metabolism
What structures make up the gastrointestinal tract?
- Mouth
- Pharynx and esophagus
- stomach
- small intestine
- large intestine
- rectum and anus
What are the accessory structures of the digestive system?
- teeth
- tongue
- salivary glands
- liver
- gallbladder
- pancreas
what are the 6 processes of digestion?
- ingestion
- secretion
- mixing and propulsion
- digestion
- absorption
- defecation
What are the 2 types of digestion?
- Mechanical
- chemical
What is mechanical digestion?
Movement of the GI tract that aids chemical digestion
What is chemical digestion?
catabolic reactions that break down carbohydrate, lipid, and protein molecules into smaller molecules that can be used by the body.
What are the layers of the GI tract?
- mucosal layer
- submucosal layer
- muscularis layer
- serosa layer
what makes up the mucosal layer?
- epithelium
- lamina propria
- muscularis mucosae
What makes up the submucosal layer?
- areolar connective tissue
- Meissner’s (submucosal) plexus (parasympathetic)
What makes up the muscularis layer?
-Muscle
Auerbach’s (myenteric) plexus (parasympathetic and sympathetic)
What makes up the serosa layer?
- visceral layer of peritoneum
- areolar connective tissue with simple squamous epithelium