Endocrine System
Explain what a tropic hormone is, name each of the 4 tropic hormones, and name the endocrine gland that secretes them.
Tropic hormones have other endocrine glands as their targets.
ACTH, FSH, LH & TSH
Anterior pituitary
Name the formed elements. Which of them is considered a complete cell and why?
Erythrocytes (RBCs), Leukocytes (WBCs) & Platelets
Leukocytes are complete cells because they have nuclei and membrane-bound organelles.
Name the 4 chambers of the heart (receiving & discharging) and the 4 valves of the heart. What is the function of valves in the heart?
Receiving chambers = right atrium & left atrium
Discharging chambers = right ventricle & left ventricle
Atrioventricular (AV) valves = tricuspid valve) & mitral/bicuspid valve
Semilunar (SL) valves = aortic SL valve & pulmonary SL valve
*Function of valves = to prevent backflow of blood
______ carry blood away from the heart, while ______ carry blood toward the heart.
Arteries; veins
Define blood pressure and name the units it is expressed in.
The force per unit area exerted on the wall of a blood vessel by its contained blood.
Expressed in mmHg
What is the largest pure endocrine gland in the body?
Thyroid gland
What are the three primary functions of the blood? Give an example of each.
Transport
Regulation
Protection
What is the cardiac cycle, what are its two phases, and how long does one cycle last?
Cardiac Cycle: all the events associated with blood flow through the heart during one complete heartbeat
2 phases = Systole (contraction of heart muscle -> forcing blood out of chambers) & Diastole (relaxation of heart muscle -> chambers refill with blood)
*Cardiac cycle lasts ~0.8 seconds
Why are veins considered "blood reservoirs"?
They contain 60% of the body's blood supply.
What is the name of the double-walled sac that encloses the heart and what are its primary functions? Additionally, name the 3 layers of the heart wall.
Pericardium:
3 layers of the heart wall:
Name the anterior pituitary hormones, each of their target organs and their actions.
Growth Hormone: liver, muscle, bone, cartilage – promotes protein synthesis for use of fats for fuel
TSH: thyroid gland – stimulates thyroid gland to release thyroid hormones
ACTH: adrenal cortex – promotes release of glucocorticoids & androgens
FSH: ovaries & testes – stimulates gamete production
LH: ovaries & testes – regulates the function of the ovaries & testes; production of estrogens/progesterone and testosterone
Prolactin (PRL): breast secretory tissue – stimulates milk production
Which of the following is true of the composition of whole blood?
a. It contains 55% plasma.
b. It contains less than 1% erythrocytes.
c. It contains 45% erythrocytes.
d. a & b
e. a & c
e. a & c
It contains 55% plasma & 45% erythrocytes.
The first sound of the heart, _____, occurs as _____ valves _____ and signifies the beginning of ventricular __________.
The second sound of the heart, _____, occurs as _____ valves _____ and signifies the beginning of ventricular __________.
The first sound of the heart, lub, occurs as AV valves close and signifies the beginning of ventricular systole.
The second sound of the heart, dup, occurs as SL valves close and signifies the beginning of ventricular diastole.
What are the 3 important sources of peripheral resistance?
1. Blood viscosity
2. Total blood vessel length
3. Blood vessel diameter
List the steps of amino acid-based hormone action.
1. Amino acid hormones bind to a receptor.
2. Binds to a G protein
3. G protein is activated as it binds GTP
4. Activated G protein activates the effector enzyme adenylate cyclase
5. Adenylate cyclase generates cAMP (2nd messenger) from ATP
6. cAMP activates protein kinases which catalyze cellular effects
Which hormone prevents wide swings in water balance, and is released by triggers such as pain, low blood pressure and drugs like morphine and nicotine?
ADH
Contrast a thrombus with an embolus.
Thrombus: stationary clot that develops and persists in an unbroken blood vessel
Embolus: a thrombus freely floating in the bloodstream
Name the 3 major waves seen on an ECG and the event that occurs at each. Additionally, name the event we are unable to see on an ECG and where it is located.
P wave: atrial depolarization of the SA node (atrial contraction)
QRS complex: ventricular depolarization (ventricle contraction)
T wave: ventricular repolarization (ventricles return to resting state)
Behind QRS complex: atrial repolarization (atria return to resting state)
In which blood vessel is systemic blood pressure the highest?
In the aorta.
Highest to lowest:
Aorta -> Arteries -> Arterioles -> Capillaries -> Venules -> Veins -> Vena Cavae
List the steps of steroid hormone action.
1. Steroid hormone diffuses through plasma membrane into its target cells
2. Bind to & activate intracellular receptors
3. The activated hormone-receptor complex travels to the nuclear chromatin
4. Complex binds to a specific region of DNA & “turns on” the gene (prompts transcription of DNA to produce messenger RNA (mRNA))
5. mRNA is translated into specific proteins, bringing about a cellular effect
Which of the following hormones would be produced in inadequate amounts in someone who is experiencing excessive thirst, high blood glucose levels and acidosis, and which endocrine gland or organ is associated with that hormone?
a. Thyroxine (T4), thyroid gland
b. Glucagon, pancreas
c. Estrogen, gonads
d. Insulin, pancreas
e. Growth hormone, pituitary gland
d. Insulin, pancreas
What is the primary function of erythrocytes? Name the protein that gives erythrocytes their color.
Function: Transportation of respiratory gases (O2 & CO2)
Hemoglobin makes RBCs red
List the pathway of the blood through the heart, beginning with the vena cava and ending with the arteries of systemic circulation.
Vena cava -> right atrium -> tricuspid valve -> right ventricle -> pulmonary SL valve -> pulmonary trunk -> pulmonary arteries -> lungs -> pulmonary veins -> left atrium -> bicuspid valve -> left ventricle -> aortic SL valve -> aorta -> arteries of systemic circulation
Name the main factors that influence blood pressure.
1. Cardiac Output (CO)
2. Peripheral Resistance (PR)
3. Blood Volume (BV)
Describe the 4 steps of hemostasis.
1. Vascular spasms: smooth muscle of torn blood vessel contracts, causing vasoconstriction, which restricts the flow of blood
2. Platelet plug formation: Platelets aggregate at site of tear to form temporary plug & release chemicals to make platelets sticky/to enhance vasoconstriction. If endothelium that lines blood vessels is damaged, platelets will stick to the collagen fibers & the protein von Willebrand factor will help stabilize the plug by creating a bridge b/w the collagen fibers & platelets
3. Coagulation: Prothrombin activator is formed -> converts prothrombin to thrombin, which catalyzes the joining of fibrinogen into a fibrin mesh. Fibrin converts plasma into a gel that allows RBCs & WBCs to become trapped in mesh as they try to pass through. Result = sealed hole at tear site that holds blood vessel in place.
4. Clot retraction & repair: Platelets contract & pull on the fibrin stands, drawing torn edges of blood vessel wall close together. Endothelial lining of blood vessel wall is restored by fibroblasts that form a connective tissue patch at the injured site. Fibrinolysis occurs over several days, removing clots that are no longer needed until the clot dissolves completely.