The Endocrine System quiz 2 Flashcards
Direct communication
- Exchange of ions and molecules between adjacent cells across gap junctions
- Two cells of the same type
- Highly specialized and rare
Paracrine communication
Uses chemical signals to transfer information from cell to cell within single tissue
- most common form of intercellular communication
Endocrine communication
Endocrine cells release chemicals(hormones) into bloodstream
- alters metabolic activities of many tissues and organs simultaneously
Target cells
Are specific cells that possess receptors needed to bind and “read” hormonal messages
Hormones
- Stimulate synthesis of enzymes or structural proteins
- increase or decrease rate of synthesis
- turn existing enzyme or membrane channel “on” or “off”
Synaptic communication
Ideal for crisis management
- occur across synaptic cleft
- chemical message is “neurotransmitter”
- limited to a very specific area
Endocrine system
-Uses chemical messengers to relay information and instructions between cells
Classes of hormones
Amino acid derivatives
Peptide hormones
Lipid derivatives
Secretion and distribution of hormones
Hormones circulate freely or travel bound to special carrier proteins
Amino acid derivatives
Are small molecules structurally relates to amino acids
- tyrosine - thyroid hormones
- tryptophan - serotonin - melatonin
The endocrine system directs ….
Long term processes such as puberty and pregnancy
Sudoriferous gland
Is NOT an endocrine gland
Gall bladder
DOES NOT contain endocrine tissue
Class of hormones that is water-soluble
Eicosanoids, amines, peptides, and proteins
Calcitonin and parathyroid
Have opposite effects in blood Ca2+ level, therefore they are considered to be antagonist
Hormone secretion is regulated by (3)
The nervous system, by other hormones; and by changes in blood composition
ADH
3 functions
Aka vasopressin; inhibits loss of water via urination; decreases loss of water via perspiration; and helps regulate blood pressure
The adrenal glands : location
Lie superior and medial to he kidneys
Inner medulla: adrenal glands
derived from embryonic ectoderm,
Outer cortex: adrenal glands
secrets hormones critical to maintenance of homeostasis
A child has sugar for all three meals. His body tried to maintain his blood glucose level w/ normal range by
Increasing insulin secretion
Fight-or-flight response
Is the body’s immediate response to a real or perceived threat to survival: elevates heart rate, respiration rates & blood glucose levels: decrease urinary and digestive functions
Hormones remain functional for less than 1 hour than … (3) distributions
Diffuse out of the blood or bind to receptors on target cells; broken down and absorbed by cells of liver or kidneys; broken down by enzymes
Presence or absence of specific receptors
Hormonal sensitivity
Amplification
magnifies effect of hormone on target cell; Binding of small number of hormone molecules to membrane receptors; leads to thousands of second messengers in cell; magnifies effect of hormone on target cell
Down-regulation
Presence of a hormone triggers decrease in number of hormone receptors; when levels are high cells become less sensitive
Up-regulation
Absence of a hormones triggers increase in number of hormone receptors; levels are low cells become more sensitive
G protein
Enzyme complex coupled to membrane receptor; link between first and second messenger
Pituitary gland
Aka hypophysis: lies within the Stella Turcica: release 9 important peptide hormones: bind to receptors
Anterior lobe of the pituitary gland
Aka adenohypophysis: hormones “turn on” endocrine glands or support other organs: three regions
Portal vessels
Blood vessels link two capillary networks in the pituitary gland
Thyroid glands
Lies anterior to thyroid cartilage of larynx: consists of two lobes: deliver nutrients & regulatory hormones
Functions is thyroid hormones
Enter target cells by transport system: affect most cells of the body: in children essential for skeletal, muscular and nervous systems
Calorigenic effect
Cell consumes more energy resulting in increased heat generation: responsible for strong, immediate, & short-lived increase in rate of cellular metabolism
Effects of PTH parathyroid hormone
Stimulate osteoclasts and inhibits osteoblasts: release calcium from bone: enhance re absorption of Ca2+ at kidneys, reduce urinary losses
Zona reticularis
Network is endocrine cells: narrow band bordering each adrenal medulla
Pineal gland
Lies posterior portion of roof of third ventricle: pea size:
Pancreas
Lies between inferior boarder of the stomach: proximal portion of small intestine: exocrine and endocrine gland
Blood glucose levels rise
Beta cells secrete insulin,
Blood glucose levels low
Alpha cells release glucagon stimulating glucose release by liver
Insulin
Peptide hormone released by beta cells
Thymus
Help develop and maintain normal immune defenses
Gonads
Testes : testosterone : secret inhidin in nurse cells, support differentiation and physical maturation of sperm
Gonads: ovaries
Estrogens:
