Ch.17 Endocrine Flashcards
What is the primary function of the endocrine system?
Release hormones into body fluids to coordinate and integrate the activity of the body’s cells.
What are hormones?
Chemical messengers secreted by cells into extracellular spaces that travel throughout the blood and regulate the metabolic function of other cells.
What is endocrinology?
The study of hormones and the endocrine organs.
List the major glands of the endocrine system.
- Pituitary
- Pineal
- Thyroid
- Parathyroid
- Adrenal
What is an endocrine gland?
A gland that secretes hormones into blood or tissue fluids without ducts.
What distinguishes exocrine glands from endocrine glands?
Exocrine glands have ducts and secrete non-hormonal products, while endocrine glands have no ducts and secrete hormones.
How do hormones affect target cells?
By altering cell activity through various mechanisms such as changing permeability, stimulating synthesis, activating or deactivating enzymes, inducing secretory activity, or stimulating mitosis.
What are the two major classes of hormones?
- Amino acid-based hormones
- Steroid hormones
What is the primary mechanism of action for water-soluble hormones?
They act on receptors on the plasma membrane and are usually coupled to intracellular second messengers via G proteins.
How do lipid-soluble hormones communicate with target cells?
They bind to intracellular receptors and directly stimulate or suppress specific genes by binding to DNA.
What is required for a cell to respond to a hormone?
The cell must have specific hormone receptors on its plasma membrane or in its cytoplasm.
What is a negative feedback mechanism in hormone regulation?
A process where high hormone levels prevent further hormone release, and low levels stimulate secretion of more hormones.
What are the three types of stimuli that control hormone release?
- Hormonal
- Humoral
- Neural
Define permissive hormones.
Hormones that must be present for a second hormone to work properly.
What are synergistic hormones?
Hormones that produce a greater effect when acting together than when acting separately.
What are antagonistic hormones?
Hormones that have opposing effects and often compete for the same receptors.
What is the pituitary gland often referred to as?
The ‘Master Endocrine Gland.’
What are the two major lobes of the pituitary gland?
- Posterior pituitary
- Anterior pituitary
What hormones are released by the posterior pituitary?
- Antidiuretic hormone (ADH)
- Oxytocin
What is the primary function of antidiuretic hormone (ADH)?
Inhibits urine production by promoting water reabsorption by the kidneys.
What does oxytocin stimulate?
Uterine contractions and milk letdown in nursing women.
What is the function of growth hormone (GH)?
Stimulates cell growth and division, particularly in bone and skeletal muscle.
Where is the thyroid gland located?
In the anterior neck, on the trachea just inferior to the larynx.
What is the main function of the thyroid hormone?
Increases basal metabolic rate and body heat, and maintains blood pressure.
What does parathyroid hormone (PTH) regulate?
Calcium homeostasis.
What are the adrenal glands known for?
Producing hormones that help the body cope with stressful situations.
What are the three layers of the adrenal cortex and their hormone types?
- Mineralocorticoids
- Glucocorticoids
- Gonadocorticoids
What is the main glucocorticoid produced by the adrenal cortex?
Cortisol.
What is the primary hormone produced by the pineal gland?
Melatonin.
What is the function of insulin?
Lowers blood glucose levels by increasing glucose transport into body cells.
What does glucagon do?
Increases blood glucose levels by stimulating glycogenolysis and gluconeogenesis.
What hormone does the heart produce?
Atrial natriuretic peptide (ANP).
What is the role of erythropoietin (EPO) produced by the kidneys?
Stimulates erythrocyte production.
What hormone is secreted by adipose tissue?
Leptin.
What hormone do osteoblasts secrete?
Osteocalcin.
Fill in the blank: The pancreas has both _______ and _______ functions.
exocrine, endocrine
Fill in the blank: The adrenal medulla secretes _______ and _______.
epinephrine, norepinephrine
What is the role of insulin in the body?
Insulin helps to create more insulin, restricts fat storage, and improves glucose handling.
What hormones are produced by the ovaries?
Estrogen and Progesterone
What hormone is produced by the testes?
Testosterone
What is cholecalciferol, and what is its function?
Cholecalciferol stimulates inactive vitamin D formation from cholesterol in skin with UV exposure.
What hormones are secreted by the gastrointestinal tract in response to food?
Gastrin, ghrelin, secretin, cholecystokinin (CCK)
Fill in the blank: The hormone (1st messenger) binds to the _______.
[receptor]
What does the receptor activate in the signaling pathway?
G protein (G_S)
What enzyme does the G protein activate?
Adenylate cyclase
What does adenylate cyclase convert ATP into?
cAMP (2nd messenger)
What are some hormones that act via cAMP mechanisms?
- Epinephrine
- ACTH
- FSH
- LH
- Glucagon
- PTH
- TSH
- Calcitonin
What is the first step in the cyclic AMP signaling pathway?
Hormone binds to receptor in membrane
What happens after the membrane receptor activates a G protein?
The G protein takes on GTP and releases GDP.
What is the outcome of cAMP activation?
cAMP activates various protein kinase signaling pathways.
What type of diabetes is mentioned in the content?
Gestational, type I and type II
