Chapter 45 Hormones and Endocrine System Flashcards
What are hormones?
Chemical signals that are secreted into circulatory system; and communicates regulatory messages within the body.
What is the endocrine system?
This is the system where there is ductless glands
What are exocrine glands?
Glands that have ducts
Where do hormones in the endocrine system go?
Goes to the bloodstream
What is the function of the endocrine system?
Chemical signaling by hormones
What is the nervous system?
Network of specialized cells—neurons—that transmit signals along dedicated pathways
What are the two criteria for signals being transmitted b/w animal cells?
- type of secreting cell
- route taken by the signal in reaching its target
What are the 5 types of intercellular signaling?
- endocrine signaling
- paracrine signaling
- autocrine signaling
- synaptic signaling
- neuroendocrine signaling
What is endocrine signaling?
Hormones are secreted into extracellular fluids by the endocrine cells via the bloodstream
What are the functions of the endocrine signaling? (3)
- maintains homeostasis
- mediates responses to stimuli
- regulates growth and development
What are local regulators?
Molecules that act over short distances, reaching target cells solely by diffusion
What happens during paracrine signaling?
Target cells lie near the secreting cells
What happens during autocrine signaling?
Target cells is also the secreting cell
What are synapses?
Neurons that form specialized junctions with target cells
What are neurotransmitters?
Molecules that diffuse short distances and bind to receptors on target cells
What are neurohormones?
Molecules that travel to target cells via the bloodstream during neuroendocrine signaling.
What secretes neurohormones?
Neurosecretory cells
What are prostaglandins?
Local regulators that function in reproduction, immune system, and blood clotting.
What does paracrine and autocrine signaling have a role in? (3)
- blood pressure regulation
- nervous system function
- reproduction
What are pheromones?
Chemicals that are released into the environment for communication
What are the functions of pheromones? (4)
- marking trails for food
- defining territories
- warning of predators
- attracting potential mates
What are the 3 types of local regulators?
- modified fatty acids
- polypeptides
- gases
What is nitric oxide?
Gas that functions in the body as both a local regulator and a neurotransmitter
What happens if oxygen levels in blood decrease?
Nitrix oxide activates an enzyme that results in vasodilation, increasing blood flow to tissues
What are the 3 types of hormones?
- polypeptides
- steroids
- amines
Which hormones are water-soluble? Which hormones are lipid/fat-soluble?
Water-soluble: Polypeptides and amines
Lipid/fat-soluble: Steroid and other nonpolar hormones
What is an example of water-soluble polypeptide?
Insulin
What is an example of water soluble amine?
Epinephrine
What is an example of a lipid-soluble steroid?
cortisol
What is an example of a lipid soluble amine?
Thyroxine
What is the cellular response pathway for water soluble hormones?
- secreted by exocytosis,
- travel freely in the bloodstream,
- bind to cell-surface receptors
What is the cellular response pathway for lipid-soluble hormones?
- Diffuses across cell membranes
- travel in bloodstream bound to transport proteins
- Diffuses into the membrane of target cells where they’ll bind to the receptors
What does signal transduction lead to? (3)
- Responses in the cytoskeleton
- Enzyme activation
- change in gene expression