Bio 224 - Unit 5 - CH 17 (Endocrine System)
How is the Signal Strength in the Amplitude Modulated System Determined?
the concentration of hormones determines the signal strength
How is the Signal Strength in the Frequency Modulated System Determined?
the frequency, not size, of the action potentials determines the signal strength
What is the Half-Life of a Hormone?
the length of time it takes for half a dose of a substance to be eliminated from the circulatory system
What are the Mechanisms of Action of Water & Lipid Soluble Hormones?
Water Soluble: bind to membrane-bound receptors → alter activity of G proteins/intracellular enzymes activate existing enzymes Lipid Soluble: bind to nuclear receptors → activate genes → synthesize new enzymes
Most Water Soluble Hormones Travel Through the Blood as Free/Bound Hormones? What About Lipid Soluble Hormones?
Water Soluble: free hormones Lipid Soluble: bound hormones
What Do Water Soluble Hormones Bind to On the Target Cell? How About Lipid Soluble Hormones?
Water Soluble: membrane-bound receptor on Lipid Soluble: a nuclear receptor in nucleus
What are 3 General Examples of Water/Lipid Soluble Hormones?
Water Soluble: proteins, peptides, amino acid derivatives Lipid Soluble: steroids, fatty acid derivatives, amino acid derivatives
What is Down-Regulation? When Does it Occur? How Does it Happen? What is the Result?
What: a decrease in the number of receptors in/on a target cell When: occurs after cells are exposed to a hormone How: receptors are being degraded faster than they are being synthesized Result: decreases sensitivity to hormones
What is Up-Regulation? What is the Result?
What: an increase in the number of receptors in/on a target cell Result: increases sensitivity to hormones
What are the 2 Lobes of the Thyroid Gland Connected By?
Isthmus
What Patterns of Secretion Do Lipid & Water Soluble Hormones Exhibit
Lipid Soluble: chronic & episodic Water Soluble: acute
What are Obstacles Lipid-Soluble Hormones Face When Traveling Through the Blood? What is the Solution to These Obstacles?
Lipid Soluble: have hard time traveling through the blood Solution: travel through blood bound to binding proteins
Which Type of Hormone (Water/Lipid Soluble) Lasts Longer in the Body?
Lipid soluble
What is the Order of Operations in the Endocrine System?
Endocrine gland/tissue → Hormones → Blood → Receptor in/on target cell → Hormone-Receptor complex → Measurable change in target cell
What are Examples of a Chemical Messenger that Can Act as a Neurotransmitter or Hormone?
Epinephrine/Norepinephrine
What Structures are Part of the Exocrine & Endocrine Portions of the Pancreas
Exocrine: acinar & duct tissue Endocrine: Islets of Langerhans
True/False: Bound Hormones Can Diffuse Through Capillary Walls and Bind to Target Tissues
False, free (unbound) hormones can pass through capillary walls to bind to target tissues
What are Free Hormones? What are Bound Hormones?
Free Hormones: hormones not bound to binding proteins Bound Hormones: hormones bound to binding proteins
Action Potentials Carried Along Axons are Described as __________________? What is Frequency? What is the Signal Type?
Frequency Modulated Signals Frequency: how often a signal is sent in a certain time period Signal Type: vary in the number of signals sent, not the amount of signal sent
What are Glands? What are the 2 Types (w/ Description)?
Glands: secretory organs Types: Endocrine: no open contact w/ exterior; no ducts; produce hormones. Exocrine: open contact w/ exterior; ducts
What Does the Endocrine System Consist Of?
glands and cells that secrete hormones into the blood
What are 4 Classes of Chemical Messengers (APEN)? Include Examples
1) Autocrine: chemical messenger (CM) stimulates the cell that originally released it (WBC cytokines) 2) Paracrine: CM released by cell and affects other types of local cells without being transported in blood (histamine, neurotransmitters) 3) Endocrine: CM released by endocrine glands, enters blood, affects distant cells 4) Neurotransmitters: CM produced by neurons & secreted into synapse to affect postsynaptic cell
What are 5 Similarities Between the Nervous & Endocrine Systems?
1) Both systems associated w/ brain 2) Both systems work together to regulate body processes 3) They may use the same chemical messenger as a neurotransmitter and hormone 4) Neurotransmitters and hormones can affect their targets through receptors linked to G proteins 5) Some neurons secrete hormones
What are 3 Main Patterns of Hormone Secretion (CEA)? Include Examples
1) Chronic: relatively constant concentration (thyroid hormone) 2) Episodic: predictable intervals & concentrations (steroid reproductive hormones) 3) Acute: sudden & irregular changes (epinephrine response to stress)
What are 3 Types of Stimuli Which Will Regulate Hormone Secretion? Give Examples
1) Hormonal Control: secretion of one endocrine gland is controlled by the hormone of another endocrine gland (Ex: seen between hypothalamus & pituitary gland) 2) Humoral Control: secretion of an endocrine gland is controlled by a substance other than a hormone (Ex: low blood Calcium causes PTH release) 3) Neural Control: secretion of an endocrine gland is controlled by the NS (Ex: neurotransmitter stimulating post-synaptic endocrine cell)
What are 3 Differences Between the Nervous & Endocrine Systems (MSD)? Provide Details
1) Mode of Transport (synapses vs blood circulation) 2) Speed of response (NS faster) 3) Duration of response (ES lasts longer)
What are 10 Functions of the Endocrine System?
1) Regulation of metabolism 2) Heart & blood pressure regulation 3) Immune system regulation 4) Ion regulation 5) Control of blood glucose 6) Control of food intake & digestion 7) Control of reproductive functions 8) Uterine contractions & milk release 9) Modulation of tissue development 10) Water Balance
What are 3 General Characteristics of Hormones (w Details)?
1) Stability (half-life) 2) Communication (interaction w/ target cell) 3) Distribution (circulate in blood)
True/False: There is a High Degree of Specificity Between Hormones and Receptor Sites on Target Cells. True/False: It Takes a High Concentration of Hormones to Activate a Significant Number of Receptors
1) True 2) False, receptors are sensitive and can be activated by a low concentration of hormones
True/False: Binding Proteins are Highly Specific. True/False: Binding Proteins are Reversible.
1) True 2) True, they can unbind from hormones
Hormones Secreted By Most Endocrine Glands are Described as __________________? What is Amplitude? What is the Signal Type?
Amplitude Modulated Signals Amplitude: total amount of signal that is produced Signal Type: fluctuations in the concentration of hormones in the bloodstream over time
What are the 2 Lobes of the Pituitary Gland? Which One is an Extension of the Hypothalamus? What Type of Hormones Do They Produce?
Anterior Lobe (Adenohypophysis): Type of Hormones: traditional hormones Posterior Lobe (Neurohypophysis): extension of the hypothalamus. Type of Hormones: neurohormones
Which Type of Hormone (Water/Lipid Soluble) Can Easily Pass Through the Membrane of a Cell? Which Can't?
Can: Lipid-soluble Can't: Water soluble
What Region of the Brain is the Hypothalamus Part Of?
Diencephalon
What are the 2 Types of Half-Lives?
Long Half-Life: regulate activities that remain at a constant rate through time (usually lipid soluble hormones) Short Half-Life: have a rapid onset and short duration (water soluble hormones)
What are the 2 Major Mechanisms of Hormone Regulation?
Negative Feedback Loop: hormone secretion is decreased/inhibited by the hormone itself once there is enough hormone in the blood to activate the target cell Positive Feedback Loop: hormone secretion is increased/stimulated by the hormone itself
Where are Your Parathyroid Glands?
On the posterior side of your thyroid gland
What Skeletal Depression Does the Pituitary Gland Rest In?
Sella Turcica
Describe Where the Pituitary Gland is in Relation to the Hypothalamus and What it is Connected By
The pituitary gland is inferior to the hypothalamus and connected to it via the infundibulum
True/False: The Endocrine System is a Control System of the Body
True
True/False: Exocrine & Endocrine Glands Can Be Found in the Same Location. Give Example
True; Ex: pancreas
What is the Common Goal of the Nervous & Endocrine Systems?
regulate/coordinate activities to achie ve/maintain homeostasis using chemical regulators
