Comprehensive Human Endocrine and Circulatory System Review for Biology Students

What type of feedback maintains homeostasis and controls hormone secretion?

Negative Feedback

What is the mechanism of hormonal action?

A hormone molecule is released into the blood and flows to a target cell with specific hormone receptors, leading to a cellular response.

What are prostaglandins?

Local hormones that target nearby tissues and cells.

How does the hypothalamus control hormone release from the pituitary gland?

The hypothalamus communicates with the anterior pituitary through blood supply and with the posterior pituitary through nerve impulses.

What is the function of Growth Hormone (GH)?

Protein anabolism and lipid catabolism.

What is the target organ of Prolactin (PRL)?

Mammary glands.

What does Thyroid Stimulating Hormone (TSH) do?

Stimulates growth and development of the thyroid gland and secretion of thyroid hormone.

What is the function of Adrenocorticotropic Hormone (ACTH)?

Stimulates growth and development of adrenal glands and secretion of glucocorticoids.

What does Follicle Stimulating Hormone (FSH) regulate in females?

Growth and development of ovarian follicles and secretion of estrogens.

What is the role of Luteinizing Hormone (LH) in males?

Stimulates growth and development of interstitial cells and testosterone secretion.

What is the function of Melanocyte Stimulating Hormone (MSH)?

Helps maintain normal skin color.

What does Antidiuretic Hormone (ADH) do?

Promotes water retention and prevents dehydration.

What is the function of Oxytocin (OT)?

Stimulates uterine contractions and milk ejection from the breasts.

What is the function of Melatonin?

Regulates biological clock and induces sleep.

What does Calcitonin (CT) do?

Decreases blood calcium levels by moving calcium from blood into bones.

What is the role of Parathyroid Hormone (PTH)?

Increases blood calcium levels by moving calcium from bones to blood.

What is the function of Aldosterone?

Promotes sodium and water retention and potassium and hydrogen loss.

What are the functions of Erythrocytes?

Carry oxygen throughout the body.

What is the function of Leukocytes?

Function in immune defense against pathogens.

What do Thrombocytes do?

Responsible for blood clotting to prevent excessive bleeding.

What are the three primary steps of hemostasis?

Vasoconstriction, platelet plug formation, and coagulation.

How does the structure of RBCs complement their function?

Their biconcave shape maximizes surface area for gas exchange and allows flexibility.

What are the eight blood types?

A+, A-, B+, B-, AB+, AB-, O+, O-.

What antibodies does Type A blood have?

Anti-B antibodies.

What happens when an Rh-negative mother has an Rh-positive baby?

The mother's immune system produces antibodies against the baby's Rh-positive red blood cells.

What are the structures of cuspid valves?

Cuspid valves consist of flaps made of thin, flexible tissue.

What is the function of cuspid valves?

Prevent backflow of blood from ventricles into atria during ventricular contraction.

What are the names of the cuspid valves?

Tricuspid Valve and Mitral (Bicuspid) Valve.

What are the names of the semilunar valves?

Pulmonary Valve and Aortic Valve.

Trace the blood flow from the vena cava to the aorta.

Vena Cava -> Right Atrium -> Tricuspid Valve -> Right Ventricle -> Pulmonary Valve -> Pulmonary Artery -> Pulmonary Vein -> Left Atrium -> Bicuspid Valve -> Left Ventricle -> Aortic Valve -> Aorta.

What is the primary pacemaker of the heart?

Sinoatrial (SA) Node

Where is the Atrioventricular (AV) Node located?

At the junction of the atria and ventricles

What is the function of the Bundle of His?

Transmits impulses from the AV node to the ventricles

What do the Right and Left Bundle Branches do?

Carry impulses along the interventricular septum to the ventricles

What are Purkinje Fibers?

A network of fibers that distribute the impulse throughout the ventricles, causing them to contract.

How does the electrical impulse travel through the heart?

It originates at the SA node, causing the atria to contract, then travels to the AV node, Bundle of His, bundle branches, and Purkinje fibers, leading to ventricular contraction.

What occurs during Atrial Systole?

Atria contract, pushing blood into the ventricles; cuspid valves are open, and semilunar valves are closed.

What happens during Ventricular Systole?

Ventricles contract, closing cuspid valves and opening semilunar valves to allow blood flow into the aorta and pulmonary artery.

What is Isovolumetric Relaxation?

Both ventricles relax with all valves closed, pressure decreases, but volume remains constant.

What occurs during Ejection in the cardiac cycle?

Blood is ejected from the ventricles into the aorta and pulmonary artery.

What happens during Ventricular Filling?

Atria fill with blood, causing cuspid valves to open and blood to flow into the ventricles.

How does an increase in Arterial Blood Volume affect Arterial BP?

It increases Arterial BP.

What is the formula for Cardiac Output?

Cardiac Output = Stroke Volume x Heart Rate.

What happens if Stroke Volume increases while Heart Rate remains the same?

Cardiac Output increases.

What is the effect of increased Peripheral Resistance on Heart Rate and Blood Pressure?

Heart Rate increases and Blood Pressure increases.

What are the three major types of blood vessels?

Arteries, Veins, Capillaries.

What is the function of arteries?

Carry oxygenated blood away from the heart.

What is the function of veins?

Carry deoxygenated blood back to the heart.

What is the function of capillaries?

Facilitate the exchange of substances between blood and surrounding tissues.

What is Systemic Circulation?

Pathway where oxygenated blood is distributed from the left side of the heart to the body and returns deoxygenated blood to the right side.

What is the pathway of Systemic Circulation?

Left ventricle → Aorta → Arteries → Arterioles → Capillaries → Venules → Veins → Superior/Inferior vena cava → Right atrium.

What is Pulmonary Circulation?

Pathway where deoxygenated blood is transported from the right side of the heart to the lungs for oxygenation.

What is the pathway of Pulmonary Circulation?

Right ventricle → Pulmonary arteries → Lungs → Pulmonary veins → Left atrium.

What is Hepatic Portal Circulation?

A specialized pathway directing blood from the gastrointestinal tract and spleen to the liver.

What is the pathway of Hepatic Portal Circulation?

Gastrointestinal tract → Mesenteric veins → Hepatic portal vein → Liver → Hepatic veins → Inferior vena cava → Right atrium.

What is blood pressure?

The force of blood against the walls of arteries.

What is the top number in blood pressure measurements?

Systolic Pressure.

What is the bottom number in blood pressure measurements?

Diastolic Pressure.

What is the pulse?

The rhythmic expansion and contraction of an artery as blood is pumped through it.

What causes the pulse?

The pressure wave created by the contraction of the heart during systole.

Where can the pulse be felt?

At various points including the radial artery, carotid artery, femoral artery, popliteal artery, and dorsalis pedis artery.

What are the purposes of hepatic portal circulation?

Nutrient processing, detoxification, and metabolism regulation.

What is the function of Umbilical Arteries?

Carry deoxygenated blood from the fetus to the placenta.

What is the function of Umbilical Vein?

Carries oxygenated blood from the placenta to the fetus.

What is the function of the Placenta?

Facilitates the exchange of oxygen, nutrients, and waste products between maternal and fetal blood.

What is the function of Ductus Venosus?

Allows oxygenated blood from the umbilical vein to bypass the liver.

What is the function of Foramen Ovale?

Allows blood to bypass the non-functioning fetal lungs.

What is the function of Ductus Arteriosus?

Connects the pulmonary artery to the aorta, allowing blood to bypass the lungs.

What are lymphatic capillaries?

Similar to blood capillaries but very permeable, with overlapping endothelial cells forming one-way mini-valves.

What are lymphatic vessels?

Collecting vessels in the skin that travel with superficial veins.

What are lymphatic trunks?

Major collecting points in the body that lymphatic vessels lead to before draining into main ducts.

What are the two lymphatic ducts?

The Right lymphatic duct and the Thoracic Duct.

What does the Right lymphatic duct do?

Receives lymph from the right upper quadrant of the body.

What does the Thoracic Duct do?

Receives lymph from the rest of the body.

What are lymph nodes?

Lymphoid organs that filter lymph and activate lymphocytes.

Where are the clinically important lymph nodes located?

Neck (cervical), armpit (axillary), diaphragm, spleen, abdominal, pelvic, inguinal, groin (femoral).

What are the primary lymphatic organs?

Bone Marrow and Thymus Gland.

What are the secondary lymphatic organs?

Lymph nodes, spleen, lymph nodules (tonsils, MALT, BALT).

What is the organization of the respiratory system?

Divided into upper respiratory tract (nose, pharynx, larynx) and lower respiratory tract (trachea, bronchi, bronchioles, alveoli).

What is the function of respiratory mucosa?

Humidifies, warms, and cleanses inhaled air.

What are the three single cartilages of the larynx?

Thyroid cartilage, Cricoid cartilage, Epiglottis.

What is the bronchial tree?

The branching structure of airways in the lungs that carries air to the alveoli.

What is the root of the lung?

The entry point where major structures like pulmonary arteries and bronchi enter and exit.

What is the hilum of the lung?

A depression on the medial surface where the root is located.

What is the base of the lung?

The inferior, concave surface that rests on the diaphragm.

What is the apex of the lung?

The superior, rounded tip that extends above the first rib.

What is the costal surface of the lung?

The lateral surface that faces the ribs.

What are lobes of the lung?

Distinct divisions within each lung, with the right lung having three lobes and the left lung having two.

What are bronchopulmonary segments?

Functionally independent sections within each lobe of the lung.

What is the parietal pleura?

The outer layer of the pleural membrane lining the thoracic cavity.

What is the visceral pleura?

The inner layer of the pleural membrane that adheres to the lung surface.

What is the process of inspiration?

Breathing in air due to diaphragm and intercostal muscle contraction.

What is the process of expiration?

Breathing out air due to diaphragm relaxation.

What is Boyle's Law in relation to pulmonary ventilation?

As lung volume increases, pressure decreases.

What are the pulmonary volumes?

Includes tidal volume, inspiratory capacity, vital capacity, and respiratory reserve volume.

What is pulmonary gas exchange?

Oxygen moves from air into blood, and carbon dioxide moves from blood into alveoli.

What is systemic gas exchange?

Oxygen diffuses from blood into cells, and carbon dioxide diffuses from cells into blood.

How are oxygen and carbon dioxide transported in the blood?

Oxygen binds to hemoglobin in red blood cells; carbon dioxide is mainly transported as bicarbonate ions.

What are the stimuli for the breathing reflex?

Includes carbon dioxide levels, oxygen levels, and pH; carbon dioxide is the most important.

What are the primary organs of the digestive system?

Mouth, Pharynx, esophagus, stomach, small intestines, large intestines, rectum, anus.