Endocrine System Flashcards
Located inferior to the hypothalamus and is connected to the hypothalamus by the infundibulum
Pituitary gland (hypophysis)
The pituitary gland is divided into which two lobes?
Anterior pituitary lobe and the posterior pituitary lobe
- also called the neurohypophysis
* composed of neurons that originate in the hypothalamus
Posterior pituitary lobe
- also called adenohypophysis
- composed of grandular tissue
- regulated by hypothalamus
Anterior pituitary lobe
What hormones are secreted or stored in the anterior pituitary lobe?
- Growth hormone (GH)
- Adrenocorticotropic hormone (ACTH)
- Thyroid-stimulating hormone (TSH)
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Prolactin (PRL)
Which hormones are stored in the posterior pituitary lobe?
- antidiuretic hormone (ADH)
* oxytocin (OXT)
- stimulates cell growth and division
* targets bones, muscles, and other tissues
Growth hormone (GH)
- stimulates release of adrenal cortex hormones
* targets the adrenal cortex
Adrenocorticotropic hormone (ACTH)
- stimulates release of thyroid hormones
* target thyroid gland
Thyroid-stimulating hormone (TSH)
- stimulates development of ova and sperm
* targets gonads
Follicle-stimulating hormone (FSH)
- stimulates secretion of sex hormones
* targets gonads
Luteinizing hormone (LH)
- stimulates milk production
* targets mammary glands
Prolactin (PRL)
- stimulates melanin production
* targets melanocytes
Melanocytes-stimulating hormone (MSH)
- stimulates water reabsorption
* targets renal tubules
Antidiuretic hormone (ADH)
- stimulates uterine contractions during labor and delivery, and release of milk
- targets uterus and mammary glands
Oxytocin (OT)
Butterfly-shaped organ located in the anterior neck, partially wrapping around the trachea just below the larynx
Thyroid gland
Work together to regulate oxygen utilization and rate of metabolism of the cells. Targets essentially every cell of the body and secreted by follicle cells
Thyroxine (T4) and Triiodothyronine (T3)
Reduces blood calcium levels by causing calcium to be deposited into bone and excreted by the kidneys
Calcitonin (CT)
Cells that secrete calcitonin are called?
Parafollicular cells or C-cells
Raises blood calcium level by causing calcium to be removed from bone and reabsorbed by the kidney. Targets bones and kidneys
Parathyroid hormone (PTH)
Microscopically the parathyroid glands are composed of?
Chief cells and oxyphil cells
Each adrenal gland is subdivided into two regions with different functions which include?
The outer cortex and the inner medulla
The adrenal cortex produces many steroid hormones, which, as a group, are called
Corticosteroid hormones
The adrenal medulla secretes the “fight or flight” hormones?
Epinephrine and norepinephrine
The adrenal cortex secreted what hormones?
- aldosterone
- cortisol
- androgens
Increase renal absorption of sodium and targets the kidneys
Aldosterone
Affects the rate of glucose metabolism and targets most cells
Cortisol
Precursors of male and female sex hormones
Androgens
Increases cardiac activity, blood pressure, and blood glucose levels and targets most cells
Epinephrine and norepinephrine
Two ovarian hormones are?
Estrogen and progesterone
Two hormones that act on ovaries?
Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH)
Signals consist of a chemical secreted by cells into the extracellular fluid to affect nearby but different types of cells.
Paracrine signal
A chemical secreted by cells into the interstitial fluid elicits effects from the same cell or cell type.
Autocrine signal
Hormone secreted into the blood and travels to affect distant tissues.
Endocrine signal
What are the three types of chemical signals?
Endocrine
Paracrine
Autocrine
Interact with their target cells and influence the cells functions in order to maintain fluid, electrolyte, and acid-base homeostasis (promotes growth, regulate metabolic reactions, etc)
Hormones
What are the endocrine glands?
Pineal gland Thyroid gland Parathyroid glands Thymus gland Adrenal glands Pancreas Gonads
Particular cells that hormones affect.
Target cells
Specific proteins to which hormones can bind.
Receptors
What are the glands of the endocrine system?
Pineal gland Thyroid gland Parathyroid glands Thymus gland Adrenal glands Pancreas Gonads
Interact with their target cells and influence the cells functions in order to maintain fluid, electrolyte, and acid-base homeostasis (promotes growth, regulate metabolic reactions, etc)
Hormones
What are the three types of chemical signals?
Endocrine signal
Paracrine signal
Autocrine signal
The hormone is secreted into the blood and travels to affect distant tissues
Endocrine signal
Chemicals secreted by cells into the extracellular fluid to affect nearby but different types of cells
Paracrine signal
Chemical secreted by the cells into the interstitial fluid elicits effects from the same cell or cell type
Autocrine signal
Organs of the endocrine system
Endocrine glands
An organ that consists of nervous tissue and secretes hormones
Neuroendocrine organ
Particular cells that hormones affect
Target cells
Specific proteins to which hormones can bind
Receptors
When the level of a particular hormone rises in the blood, certain target cells will produce more receptors for that hormone
Up-regulation
Prolonged exposure to a high level of a given hormone causes target cells to decrease in the number of receptors specific for that hormone
Down-regulation
What are the two classes of hormones?
Amino acid-based
Steroid
A hormone that consists of one or more amino acids, hydrophilic and so bind to the plasma membrane receptors
Amino acid-based hormone
Cholesterol derivatives with a core of hydrocarbon rings, hydrophobic and so interact with plasma membrane or intracellular receptors
Steroid hormone
Enzyme that catalyzes the formation of the second messenger cyclic adenosine monophosphate (cAMP) from ATP.
Adenylate cyclase
Enzymes that catalyze the transfer of a phosphate group from ATP to another molecule (phosphorylation).
Protein kinases
Hormones that act on the same target cell to exert the same effect.
Synergists
Hormones that act on the same target cell to expert opposite effects
Antagonists
The hypothalamus is connected to the pituitary gland (hypophysis) by a stalk called?
Infundibulum
The hormone that controls water balance
Antidiuretic hormone (ADH)
Lack of ADH secretion or activity
Diabetes insipidis
Hormone that supports reproduction and milk release
Oxytocin
Positive feedback loop that induces lactation in an hungry infant to suckle which stimulates milk release. When the infant becomes full and stop suckling the feedback loop is broken.
Milk let-down reflex
Stimulate the release of hormones from the anterior pituitary.
Releasing hormone
Inhibits the release of hormones from the anterior pituitary.
Inhibiting hormone
GH hypersecretion occurs before closure of epiphyseal plates
Gigantism
GH hypersecretion occurs after closure of the epiphyseal plates
Acromegaly
GH hypersecretion prior to closure of the epiphyseal plates
Pituitary dwarfism
Connects the right and left lobes of the thyroid gland
Isthmus
A protein rich gelatinous material that fills the interior of a follicle
Colloid
The spheres in the thyroid gland
Thyroid follicles
Clusters of cells between the thyroid follicles that produce calcitonin
Parafollicullar cells
Hormone secreting cells that produce parathyroid hormone
Chief cells
Overproduction of the thyroid hormone
Hyperthyroidism
Underproduction of the thyroid hormone
Hypothyroidism
A type of hyperthyroidism which results from the immune system producing abnormal proteins that mimic the actions of TSH on the thyroid gland,
Graves’ disease
An enlargement of the thyroid gland
Goiter
When an infant is born with inadequate thyroid function
Congenital hypothyroidism
Occurs when the calcium ion level in the blood increases above normal
Hypercalcemia
Regulate the concentration of certain minerals in the body such as sodium and potassium ions (fluid and electrolyte homeostasis)
Mineralocorticoids
Hypersecretion of aldosterone that causes abnormally low extracellular concentration of potassium ions
Hypokalemia
Hypersecretion of aldosterone that causes abnormally high extracellular concentration of sodium ions
Hypernatremia
Produced in the zone fasciculata and sons reticularis and their main role is to help mediate the body’s response to stress (metabolic homeostasis)
Glucocorticoids
Series of changes that maintains homeostasis when the body is faced with a stressor (exercise, emotional excitement, etc)
Stress response
Oversecretion of cortisol from the adrenal cortex, usually from a tumor
Cushing disease
Hyposecretion of aldosterone and cortisol
Addison’s disease
Sex hormones that affect the reproductive organs, or gonads, and multiple other tissues
Androgenic steroids
Neuroendocrine cells in the adrenal medulla that derive from nervous tissue
Chromaffin cells
Small round islands of endocrine cells in the pancreas that secrete hormones into the bloodstream
Pancreatic islets (islets of Langerhans)
Exocrine cells in the pancreas that are located around small ducts, into which they secrete enzymes and other products that are delivered into the digestive tract
Acinar cells
What are the two groups of cells in the pancreas?
Pancreatic islets
Acinar cells
What are the three main cell types of the islets?
Alpha cells
Beta cells
Delta cells
Secrete the peptide hormone glucagon
Alpha cells
Secrete the protein hormone insulin
Beta cells
Secrete the peptide hormone somatostatin
Delta cells
When insulin levels rise to high and the blood glucose level drops
Hypoglycemia
When insulin levels decrease and blood glucose levels becomes elevated
Hyperglycemia
What are the two most common causes of hyperglycemia?
Diabetes mellitus 1 and 2
What are the two hormones secreted by the thymus?
Thymosin
Thymopoietin
What hormone does the testes secrete?
Testosterone
Wants are the two types of gonads?
Testes (sperm)
Ovaries (Ova/Eggs)
What are gametes?
Sperm and Ova/Eggs
What hormone does adipose tissue secrete?
Leptin (promotes satiety)
What hormone does the cardiac muscle cells secrete?
Atrial natriuretic peptide (ANP)
What hormones does the kidneys secrete?
Erythropoietin production (EPO)
Renin
Conversion of vitamin D
