Chapter 18 - The Endocrine System Flashcards
Compare Nervous and Endocrine System?
Nervous and Endocrine Systems act together to coordinate all systems of the body
Nervous System:
Release Neurotransmitters that bind to receptors on Target Cells (specific)
Endocrine System:
Release Hormones (to excite), most circulate in blood and bind to receptors on Target Cells (specific)
What is Endocrine Secretions in General?
Endocrine secrete Hormones released by:
1- Endocytosis (in)
2- Exocytosis (out)
Hormones then go into Blood the Target Cells
ex:
Mitochondria - Metabolic rate
Lysosome - Secretion
Myosin Fibers - Contraction rate
Centriole - Mitotic rate
Cell Membrane - Polarity and permeability
What is the Molecule of Nervous vs Endocrine Systems?
Nervous:
Neurotransmitters released locally in response to nerve impulses
Endocrine:
Hormones delivered to tissues throughout body by blood
What is the Site of Action of Nervous vs Endocrine Systems?
Nervous:
Close to site of release, at synapse
Binds to receptors in postsynaptic membrane
Fast response
Highly specific
Endocrine:
Far from site of release (usually)
Binds to receptors on or in Target Cells
Delayed response
Better for slow responses
What is the Types of Target Cells of Nervous vs Endocrine Systems?
Nervous:
Muscle cells
Gland cells
Other neurons
Endocrine:
Cells throughout body
Many more than nervous
What is the Time to Onset of Action of Nervous vs Endocrine Systems?
Nervous:
Typically milliseconds
Very fast
Endocrine:
Seconds to hours or days
Very efficient but longer
What is the Duration of Action of Nervous vs Endocrine Systems?
Nervous:
Brief
Right away
Endocrine:
Longer
What is Exocrine Glands?
Exocrine Glands:
Secrete products into ducts
None are Hormones
Include:
1- Sudoriferous (Sweat) Glands
2- Sebaceous (Oil) Glands
3- Mucous Glands
4- Digestive Glands
5- Others throughout body
What is Endocrine Glands?
Endocrine Glands:
Secrete Hormones
Do not have ducts
They secrete Hormones directly into Interstitial Fluid that surrounds them
Hormones diffuse into Bloodstream through Capillaries and are carried to Target Cells throughout body
Include:
1- Pituitary Gland
2- Thyroid Gland
3- Parathyroid Gland
4- Adrenal Gland
5- Pineal Gland
What is Secreting Cells?
Secreting Cells:
Certain organs and tissues that are not part of the Endocrine System also secrete Hormones through their Secreting Cells
Secreting Cells can be found in:
1- Hypothalamus
2- Thymus
3- Pancreas
4- Ovaries
5- Testes
6- Kidneys
7- Stomach
8- Liver
9- Small Intestine
10- Skin
11- Heart
12- Adipose Tissue
13- Placenta
What is Target Cells?
Hormones traveling throughout body will only affect Target Cells that possess specific Protein Receptors for the Hormone
Receptors are continually being synthesized and broken down
Very divers
Very specific
On surface of Target Cells
(shape - specificity)
What is Down-Regulation?
Receptors may be Down-Regulated in presence of high concentration of Hormone
What is Up-Regulation?
Receptors may be Up-Regulated in presence of low concentration of Hormone
What is the Basic Pathway of Hormones?
Endocrine Cell release Hormones
Hormones go into Blood
Hormones travel in body
Hormones diffuse out of Blood Capillaries
Hormones bind to Receptors on Target Cells
What is Paracrine Hormones (Local Hormones)?
Paracrine Hormones affect neighboring Target Cells
What is Autocrine Hormones?
Autocrine Hormones affect the same cell that secreted them
What is Hormones’ Solubility Types?
Hormones are either:
1- Lipid-soluble
or
2- Water-Soluble
What is Lipid-Soluble Hormones?
Lipid-Soluble Hormones:
Circulate in blood bound to Transport Protein
Nonpolar
ex:
Steroid Hormones
Thyroid Hormones
Nitric Oxide
What is Water-Soluble Hormones?
Water-Soluble Hormones:
Circulate freely in Plasma
Polar
ex:
Amine Hormones
Peptide and Protein Hormones
Eicosanoid Hormones
What is Steroid Hormones?
Lipid-Soluble
(Fatty, non-polar)
1- Adrenal Cortex:
Aldosterone
Cortisol
Androgens
2- Kidneys:
Calcitriol (Active form of Vitamin D)
3- Testes:
Testosterone
4- Ovaries:
Estrogens
Progesterone
What is Thyroid Hormones?
Lipid-Soluble
(Gassy)
1- Thyroid Gland (Follicular Cells):
T3 (Triiodothyronine)
T4 (Thyroxine)
2- Endothelial Cells lining Blood Vessels:
Nitric Oxide (NO)
What is Amines?
Water-Soluble
(Amino group N, ex: NH2)
1- Adrenal Medulla:
Epinephrine
Norepinephrine (Catecholamines)
2- Pineal Gland:
Melatonin (sleep)
3- Mast Cells in connective tissues:
Histamine (allergies)
4- Platelets in blood:
Serotonin
What is Peptides and Proteins Hormones?
Water-Soluble
1- Hypothalamus:
All Hypothalamic Releasing and Inhibiting Hormones
2- Posterior Pituitary Gland:
Oxytocin
Antidiuretic Hormones (ADH)
3- Anterior Pituitary Gland:
Growth Hormone (GH)
Thyroid-Stimulating Hormone (TSH)
Adrenocorticotropic Hormone (ACTH)
Follicle-Stimulating Hormone (FSH)
Luteinizing Hormone (LH)
Prolactin (PRL)
Melanocyte-Stimulating Hormone (MSH)
4- Pancreas:
Insulin
Glucagon
Somatostatin
Pancreatic Polypeptide
5- Parathyroid Glands:
Parathyroid Hormone (PTH)
6- Thyroid Gland (Parafollicular Cells):
Calcitonin
7- Stomach and Small Intestine (Enteroendocrine Cells):
Gastrin
Secretin
Cholecystokinin (CCK)
Glucose-Dependent Insulinotropic Peptide (GIP)
8- Kidneys:
Erythropoietin
9- Adipose Tissue:
Leptin
What is Eicosanoids?
Water-Soluble
1- All cells except RBC:
Prostaglandins
Leukotrienes
(Released everywhere except RBC)