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59 Cards in this Set

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What does the endocrine system basically do?
Influences metabolic activities via hormones
What are the glands of the endocrine system?
Fill this in with Tammie's notes.
Give some examples of tissues/organs that produce hormones
adipose cells
thymus
cells in walls of small intestine
stomach
kidneys
heart
What functions does the hypothalamus have?
neural and endocrine
What are the 3 chemical messengers?
Hormones
Autocrines
Paracrines
Describe basically hormones.
long-distance chemical signals in blood or lypmh
Describe basically Autocrines
exert effects on same cells that secrete them
Describe basically Paracrines
locally acting chemicals
affect cells other then those that secrete them
Where are hormones found in?
Blood and lymph
What are the 2 classes of hormones?
Amino-acid based
Steroids
What are steroids made from?
Cholesterol
Where do steroids come from? What area?
Gonadal and adrenocortical hormones
What are the amino-acid based hormones made from?
Amines
Thyroxine
Peptides
Proteins
What do hormones do to target cells? (1 or more)
Alter plasma membrane permeability
Stimulate synthesis of proteins or regulatory molecules
Activate or deactivate enzyme systems
Induce secretory activity
Stimulate mitosis
How do hormones alter the plasma membrane permeability?
By closing or opening ion channels..
What thing can water-soluble hormones NOT do?
Enter target cells
What things do water-soluble hormones act on?
Plasma membrane receptors, because they cannot enter the cells.
What are lipid-soluble hormones come from?
Steroid and thyroid hormones
What do lipid soluble hormones act on?
Intracellular receptors, directly activate genes.
What are the 5 actions in Cycle AMP signaling?
1. Hormone(1st messenger) binds to receptor
2. Receptor activate G protein
3. G protein activates adenylate cyclase
4. Adenylate cyclase converts ATP to cAMP(2nd messenger)
5. cAMP activates protein kinases
How is cAMP activated?
kinases phosphorylate
various proteins
activating some, inactivating others
What rapidly degrades cAMP?
phosphodiesterase, once it enters the cell it begins to decrease
What amplifies cAMP reactions?
Intracellular enzymatic cascades
What is phosphodiesterase?
Inside of a cell
What is PIP2 calcium signaling used by?
Amino-acid based hormones in some tissues
What protein does PIP2 calcium signaling involve?
G
What does Ca2+ alter?
Enzymes or channels or binds to regulatory protein calmodulin
What does DAG do?
It activates protein kinases
IP3 triggers release of Ca2+
What are the 5 steps of Steroid hormones and thyroid hormones?
1. Diffuse into target cells - bind with intracellular receptors.
2. Receptor-hormone complex enters nucleus
3. Receptor-hormone complex binds to a specific region of DNA
4. This prompts DNA transcription to produce mRNA
5. mRNA directs protein synthesis
What 3 factors does target cell activation depend on?
1. blood levels of hormone
2. relative number of receptors on or in target cell
3. Affinity of binding between receptor and hormone
What is Up-regulation?
target cells form more receptors in response to the hormone
What is down-regulation?
target cells lose receptors in response to the hormone
What two ways do hormones influence receptors?
Up and Down Regulation
How do steroids and thyroid hormones circulate?
Bound to something
What are the two factors of concentration of circulating hormones?
Rate of release
Speed of inactivation and removal
In what ways are hormones removed from the blood?
Degrading enzymes
Kidneys
Liver
Half-life
What are the 3 ways that multiple hormones interact?
Permissiveness
Synergism
Antagonism
What is Permissiveness?
1 hormone can't exert its effects without another hormone being present
What is Synergism?
more than 1 hormone produces same effects on target cell
What is Antagonism?
1 or more hormones opposes action of another
How is the blood level of hormones controlled?
Negative feedback
Vary only within narrow desiarable range
How are hormones synthesized and released, in response to?
Humoral stimuli
Neural stimuli
Hormonal stimul
What things directly simulates secretion of hormones?
Changing blood levels of ions and nutrients
Which nerve fibers stimulate hormone release and how?
Sympathetic nervous system fibers stimulate adrenal medulla to secrete catecholamines
What is special about hormonal stimuli?
Hormones that stimulate release of more hormones.
What do hypothalamic hormones stimulate?
Anterior pituitary hormones.
What do anterior pituitary hormones stimulate?
More hormones in the body.
What is the hypothalamic-pituitary-target endocrine organ feedbook loop talking about?
Hormones from final target organs inhibit release of anterior pituitary hormones.
How does the nervous system modify the endocrine system? EXAMPLE
Nervous system modifies stimulation of endocrine glands and their negative feedback mechanisms.

Severe stress:
Hypothalamus and sympathetic nervous system activated.
Glucose levels rise.
What are the 2 major lobes of the pituitary gland?
Posterior
Anterior
What is the posterior lobe of the pituitary gland?
Pituicytes(glial-like supporting cells) and nerve fibers
What is the anterior lobe of the pituitary gland?
Glandular tissue
(adenohypophysis)
What does the posterior lobe of the pituitary gland do?
1. Downgrowth of hypothalamic neural tissue
2. Neural connection to hypothalamus
3.Nuclei of hypothalamus synthesize neurohormones oxytocin and ADH
4.Neurohormones transported to posterior pituitary.
What is the structure of the Anterior lobe of the pituitary gland?
Hypophyseal portal system
- Primary capillary plexus
- Hypophyseal portal veins
- Secondary capillary plexus
What does the Anterior Lobe of the pituitary gland?
Carries releasing and inhibiting hormones to anterior pituitary to regulate hormone secretion
Which protein doesn't activate cAMP 2nd messenger system?
GH
Which proteins regulate secretory action of other glands?
TSH
ACTH
FSH
LH
What does Growth Hormone do?
1. Stimulates most cells - targets bone and skeletal muscle
2. Promotes protein synthesis - encourages use of fats
3. Most effects mediated indirectly by insulin-like growth factors (IGFs)
What are the direct actions of Growth Hormone?
1. Stimulates Liver, skeletal muscle, bone, cartilage to produce growth factors
2. mobilizes fat - elevates glucose by decreasing glucose uptake and encouraging glycogen breakdwon(anti-insulin effect of GH)