Endocrine Quiz Review

Terms

1.       Endocrine Gland

• a gland that secretes hormones into the bloodstream, where they travel to distant organs, tissues, and cells

• secretions regulate metabolism, growth, reproduction, and homeostasis

2.       Exocrine Gland

• a gland that secretes its secretions into ducts onto epithelial surfaces, NOT the bloodstream

• examples: skin & digestive tract

• secretions are enzymes, sweat, mucus, etc, NOT hormones

3.       Central Dogma of Biology

• theory that states genetic information only flows in 1 way: DNA → RNA → Protein

• DNA in the cell is transcribed into messenger rNA that is translated into proteins that act as enzymes, receptors, and carrying out most cellular functions

• possible transfer of information: nucleic acid → nucleic acid & nucleic acid → protein

• impossible transfer of information: protein → protein & protein → nucleic acid

4.       Half-Life

• the amount of time required for half of a given substance to be metabolized, inactivated, or removed from circulation

• reflects stability and clearance rate

5.       Receptors

• specialized proteins located on the cell’s surface or inside of it

• binds hormones and neurotransmitters to initiate a cellular response such as second messenger activation, gene transcript, or enzyme activity

• has specific 3D shapes and its binding site is shaped to recognize only certain hormones

• lock and key, hormones are the key & receptors are the lock

6.       Hormone half-life

• how long it takes for a hormone’s concentration to drop down to 50% of its original level

• affected by excretion (kidneys filter hormones out of the body through urine), absorption (hormones’ entry into blood from administered hormones, medications, and drugs), and degradation (breakdown of hormones by enzymes)

7.       Gluconeogenesis

• metabolic process of making glucose from non carbohydrate precursors like amino acids, lactate, and glycerol

• occurs in the liver

• vital during fasting or starvation to maintain blood glucose levels for the brain and red blood cells

8.       Diabetes mellitus

• hyperglycemia/high blood sugar (glucose) & endocrine/metabolic disorders

• problems with insulin secretion

       

9.       Gonads

• reproductive organs (testes & ovaries)

• produce gametes (sperm & eggs)

• secrete sex hormones (testosterone, estrogen, progesterone)

• regulates secondary sexual characteristics, reproduction, and other endocrine functions

10.   Perfusion

• delivering blood through the capillary bed → tissues and organs

• ensures oxygen, nutrient supply, and removal of metabolic waste

• important for normal tissue function

• poor perfusion leads to ischemia (less blood flow) and cell death

Also……

Know your hormones! (The chart – see below)

Concepts:

1. Name 2 hormones and what stimulates them to be released/what signal or condition in the body makes a gland secrete that hormone

• epinephrine-

  • released from the adrenal medulla to the target organs such as the heart and blood vessels

  • released when the body is under stress, physically active or exercising, or scared in danger

  • sympathetic nervous system stimulates the secretion of the hormone as a “fight or flight” response

• cortisol-

  • the hypothalamus releases corticotropin releasing hormone → which secretes ACTH adrenocorticotropic hormone from the anterior pituitary gland → adrenal glands make cortisol in response to ACTH production

  • secreted during stress & low blood glucose

  • released from the adrenal cortex to the bloodstream and everywhere in the body because it’s a steroid hormone and is fat soluble, but its main targets are

    • immune system - suppresses inflammation and immune response

    • liver - increases glucose

    • muscle - breaks down protein for energy

    • fat tissue - breaks down fat for energy

2. Name at least four changes that hormones can cause in target cells.

 1.change in cell membrane permeability-

• water soluble hormones bind to cell receptors on the cell membrane

• that activates second messenger

• the second messenger activates the opening and closing of ion channels in the cell, letting ions move in and out, essentially changing the electrical excitability in the cell

2. activates or deactivates enzymes-

• water soluble hormones bind to cell membrane receptors outside of the cell to activate second messengers from the cell that can add or remove phosphate groups that can turn enzymes on and off, the more an enzyme is activated and turned on, the more action and production that goes on the in body such as speeding up glycogen breakdown and gluconeogenesis

• fat soluble hormones bind to intracellular receptors that act on DNA, changing DNA expression and gene transcription. the hormone response elements on DNA sequences that were attached in the nucleus or cytoplasm turns genes on or off, causing the cell to make more or less of the proteins and enzymes

3. stimulates mitosis

• hormones bind to receptors on the cell surface or onto intracellular receptors that act on DNA. in response to the hormone binding to the receptors, the receptors send a signal to the nucleus to activate genes that control the cell cycle. those genes make proteins that start cell division

4. stimulates protein synthesis

• hormone binds to receptor, hormone receptor complex sends signals to genes in the nucleus to turn on, transcription of mRNA happens where the DNA instructions for protein are made, ribosomes in the cell read the mRNA instructions and assemble amino acids into specific protein

3. What are the three stimuli that can cause hormone synthesis/release/retention?

1. humoral stimulus- changes in blood ion/nutrient/concentration levels

2. neural stimulus- nerve fibers stimulate hormone release

3. hormonal stimulus- hormones tell glands to release/retain hormones

4. What are the only two hormones released from the posterior pituitary gland? Where are they made?

the only two hormones released from the posterior pituitary gland are oxytocin and anti-diuretic hormone and they are both made in the hypothalamus

5. Why does the thyroid gland have follicles?

 the thyroid follicles are the functional and primary unit of the thyroid gland. they are responsible for the secretions of the thyroid hormone and hold colloid that is made up of thyroglobulin and iodine molecules that have thyroid hormone precursors.

6. What is main difference in mode of action in amino-acid based vs. steroid-based hormones?

the cell membrane is made up of a phospholipid bilayer, which is fat. amino acid based hormones cannot enter the cell membrane because they are water based and do not dissolve with fats. their receptors are located on the cell membrane’s surface, so they need second messenger activation to get their signals to their target organs. steroid based hormones are lipid soluble so they can easily pass through the cell membrane and attached to their intracellular receptors there in the nucleus and cytoplasm to send their messengers to their target organs.

7. How do hormones affect homeostasis?

• hormones maintain homeostasis in the body by sensing deviations and abnormalities in the body from sources and respond to them by sending signals to target organs via feedback loops. hormones can affect metabolism, enzyme activity, cell activity, growth, reproduction, and stress response.

• negative feedback loops maintain homeostasis by the hormone’s effect reduces the stimulus for its own secretion such as cortisol & positive feedback loops that amplifies the process such as oxytocin

• example: insulin lowers glucose and glucagon raises glucose to balance glucose levels

quiz format is matching and open ended writing

10 hormones and match what is their source tissue/organ/cell and what is the target tissue/organ/cell

thyroid hormone, aldosterone

why is there a different blood supply between the anterior and posterior gland

15 questions in total, so 5 open ended writing