Endocrine System Flashcards
Hormones
Chemical signals secreted into circulatory system that communicate regulatory messages
What cells respond to hormones
target cells
Exogenous chemicals
interfere with hormone signaling.
Insecticides, herbicides, dyes, plastics, detergents
How do hormones work
Chemical signals bind to receptor proteins on target cells.
Exocrine glands
Have ducts and secrete substances onto body surfaces or into body cavities.
(tear ducts, sweat glands, salivary glands, liver, pancreas, mammary glands, stomach)
Local regulators
chemical signals that travel over short distances by diffusion
What do local regulators help regulate
blood pressure, nervous system function, and reproduction.
Paracrine signals
act on cells near secreting cell
Autocrine signals
act on secreting cell itself
Pheromones
chemical signals that are released from the body and used to communicate with other individuals in the species
Three major classes of molecules that function as hormones in vertebrates
Polypeptides
amines
steroid hormones
Lipophilic hormones (steroid hormones)
pass through cell membrane
travel in bloodstream bound to transport proteins and diffuse through membrane of target cells
Hydrophilic hormones
do not pass easily through membrane
secreted by exocytosis, travel freely in bloodstream, bind to cell-surface receptors
Binding of a hormone to its receptor initiates a ___
Signal transduction pathway which leads to responses in the cytoplasm, enzyme activation, or a change in gene expression
Where is vitamin D formed
In the skin of vertebrates
Where is Vitamin D transported
to the liver
converted to physiological active form
What does vitamin D regulate
calcium and phosphate in the blood
cell proliferation and apoptosis
Neuromuscular function
Gland hyposecretion
To little hormone
Gland hypersecretion
too much hormone
Pineal Gland
Melatonin
Pancreas gland
insulin/glucagon
Adrenal Medulla gland
Epinephrine and Norepinephrine
Adrenal cortex gland
Glucocorticoids and Aldosterone
Parathyroid gland
Parathyroid hormone
Thyroid gland
Thyroxine, Triiodothyronine, Calcitonin
Anterior Pituitary Gland
Prolactin, TSH, ACTH, FSH, LH, MSH, Growth Hormone
Posterior Pituitary Gland
Oxytocin, ADH
Negative feedback loop
inhibits a response by reducing initial stimulus
Regulates many hormonal pathways
Insulin and glucagon
antagonistic hormones that help maintain glucose homeostatis
What produces glucagon and insulin
Pancreas has clusters of endocrine cells called pancreatic islets (islets of Langerhand) with alpha cells that produce glucagon and ceta cells that produce insulin
alpha cells
produce glucagon
beta cells
produce insulin
Insulin
Reduces blood glucose levels
How does insulin reduce blood glucose levels
promotes the cellular uptake of glucose
Slows glycogen breakdown in liver
Promoting fat storage
Glucagon
increases blood glucose levels
How does glucagon increase blood glucose levels
stimulating conversion of glycogen to glucose in the liver
stimulating breakdown of fat and protein into glucose
Type 1 diabetes mellitus (insulin-dependent)
The immune system destroys pancreatic beta cells
Type 2 diabetes mellitus (non-insulin dependent)
Involves insulin deficiency or reduced response of target cells due to change in insulin receptors
What can diabetes lead to
Peripheral neuropathy, wounds, infections, nephropathy, retinopathy
Peripheral neuropathy
diabetes damages the nerves
wounds
diabetes affects circulation, reducing the body’s ability to heal when damage occurs
Infections
Diabetes slows the body’s response to infections
Antibody response is slow in type 1
Poor circulation`
Nephropathy
Kidney disease (affects proteins that are involved in wound healing)
Retinopathy
eye disease/blindness
Oxytocin
induces uterine contractions and the release of milk
How is oxytocin released
suckling sends a message to the hypothalamus via the nervous system to release oxytocin, which further stimulates milk glands
Antidiuretic hormone (ADH)
enhances water reabsorption in the kidneys
Influence of hormones on insects
influence molting and metamorphosis
How do insects molt
Brain hormone stimulates prothoracic gland to produce ecdysone, or molting hormone
high levels cause molting
How does metamorphosis occur
Corpora allata produces juvenile hormone
low levels result in metamorphosis
juvenile hormone
causes metamorphosis in insects
Where are the adrenal glands
adjacent to the kidneys
adrenal medulla
secretes epinephrine (adrenaline) and norepinephrine (noradrenaline)
what class of hormones are epinephrine and norepinephrine
catecholamines
What do epinephrine and norepinephrine do
Trigger release of glucose and fatty acids into the blood
Increase oxygen delivery to body cells
Direct blood toward heart, brain, skeletal muscles, and away from skin, digestive system, and kidneys
