Week 12: Endocrine Flashcards
Hormones are transported primarily via what?
The bloodstream
Where do hormones bind?
Receptors on target cells
What do endocrine glands do?
They secrete their hormones directly into the surrounding fluid.
Describe the three types of stimuli for hormone releases?
- Neural: Parasympathetic NS (ACh/Insulin), sympathetic NS (ACh, epinephrine), posterior pituitary hormones
- Hormonal: Hypothalamic/anterior pituitary pathways
- Humora: Ions/molecules in the environment, high glucose/insulin, low glucose/glucagon
Hormones are released into the blood and only travel to target cells in the body. True or false?
False. They travel to all cells, but only target cells (with a specific hormone receptor) respond.
What two things dictate the response of a target cell?
- The specific type of receptor
- The specific intracellular signaling pathways
Response levels depend on what?
The level of the hormone
(Response decreases as hormone is cleared from body)
Where is the receptor for steroids?
The cytoplasm or nucleus
Where is the receptor for proteins and amine?
The cell membrane
What kind of signaling pathways are initiated by steroids?
Activation of genes for transcription and translation
What kind of signaling pathways are initiated by proteins and amines?
Activation of second messenger systems
What is the half-life length of steroids, proteins, and amines?
Steroids: Long
Proteins: Short
Amines: Short
What is the stimuli for cortisol?
Circadian rhythm and stress
Where does cortisol come from?
The adrenal cortex
What are cortisol’s four targets and actions?
- Immune system: Suppressed
- Liver: Gluconeogenesis
- Muscle: Protein catabolism
- Adipose tissue: Lipolysis
What are whole body level responses to cortisol?
Increases available energy and prioritizes energy use for stress response
What is the hormone that is reponsible for ecdysis (extrusion from exoskeleton) in crustaceans?
Edysone
What types of hormones are involved in the molting process?
Neural and hormonal
MIH inhibits the release of ecdysone from the Y organ. True or false?
True
When MIH levels in the plasma of a crustacean are high, ecdysone levels tend to be low. True or false?
True; MIH inhibits ecdysone
MIH receptors in molting crustaceans are located on the X organ.
False. They’re located on the Y organ.
Cortisol inhibits the release of ACTH from the hypothalamus. True or false?
False.
Cortisol inhibits the release of ACTH from the anterior pituitary.
CRH comes from the hypothalamus.
In humans, cortisol receptors are found in the hypothalamus and liver. True or false?
True
When CRH levels in the plasma of a human are high, ACTH levels will be low. True or false?
False. ACTH levels will be high.
Suppose a human had high (excess) levels of cortisol. What would be the levels of CRH and ACTH in their plasma.
Low plasma CRH and low plasma ACTH. Cortisol inhibits both.
