unit1final

Question 1

Describe the functions of the endocrine system.

Answer 1

Reproduction: Hormones regulate sexual development and reproductive processes.
Growth and Development: Hormones like growth hormone influence physical growth and development.
Homeostasis: It maintains electrolyte, water, and nutrient balance in the blood.
Metabolism: Hormones regulate cellular metabolism and energy balance.
Defense: It mobilizes body defenses against stress and infection

Question 2

Amino Acid-Based Hormones

Answer 2

Solubility: These hormones are generally water-soluble, except for thyroid hormone.
Receptor Interaction: They act on receptors located in the plasma membrane. Since they cannot cross the lipid bilayer, they use second messengers, often involving G proteins, to relay signals inside the cell.
Examples: Epinephrine and thyroxine.
Steroid Hormones:

Question 3

Steroid Hormones

Answer 3

Solubility: Steroid hormones are lipid-soluble.
Receptor Interaction: They can cross the plasma membrane and bind to receptors inside the cell. This interaction directly activates genes, leading to changes in protein synthesis.
Examples: Cortisol and aldosterone.

Question 4

Humoral Stimuli - stimuli that activate endocrine glands

Answer 4

These involve changes in the levels of certain ions or nutrients in the blood. For example, the parathyroid glands release parathyroid hormone in response to low calcium levels, and the pancreas releases insulin in response to high blood glucose levels.

Question 5

Identify 3 types of stimuli that activate endocrine glands.

Answer 5

humoral, neural, hormonal

Question 6

Neural Stimuli - stimuli that activate endocrine glands

Answer 6

These occur when nerve fibers stimulate hormone release. A classic example is the adrenal medulla releasing epinephrine and norepinephrine in response to stress signals from the sympathetic nervous system.

Question 7

Hormonal Stimuli - stimuli that activate endocrine glands

Answer 7

These involve hormones from one endocrine gland stimulating another gland to release its hormones. For instance, hormones from the hypothalamus stimulate the anterior pituitary gland, which then releases hormones that affect other endocrine glands like the thyroid and adrenal cortex.

Question 8

Up/Down Regulation

Answer 8

Hormone receptors on target cells are dynamic. High levels of a hormone can lead to down-regulation, reducing receptor numbers to decrease sensitivity. Conversely, low hormone levels can cause up-regulation, increasing receptor numbers to heighten sensitivity.

Question 9

Synergism

Answer 9

This occurs when two or more hormones produce the same effects on a target cell, and their combined effects are amplified. For example, glucagon and epinephrine both promote glucose release from the liver, and together they release more glucose than individually.

Question 10

Antagonism

Answer 10

This is when one hormone opposes the action of another. Insulin and glucagon are classic examples; insulin lowers blood glucose levels, while glucagon raises them. Antagonism can occur through competition for receptors or different metabolic pathways.

Question 11

Anterior Pituitary Hormones:

Answer 11

Growth Hormone (GH): Promotes growth and metabolic functions.
Thyroid-Stimulating Hormone (TSH): Stimulates thyroid hormone release.
Adrenocorticotropic Hormone (ACTH): Stimulates adrenal cortex to release cortisol.
Follicle-Stimulating Hormone (FSH) & Luteinizing Hormone (LH): Regulate reproductive processes.
Prolactin: Stimulates milk production.

Question 12

thyroid hormone

Answer 12

thyroxine (T4) & Triiodothyronine (T3)Regulate metabolism and energy balance.

Question 13

adrenal gland hormones

Answer 13

Adrenal Gland Hormones:

Mineralocorticoids (Aldosterone): Regulate sodium and potassium balance.
Glucocorticoids (Cortisol): Manage stress response and metabolism.
Catecholamines (Epinephrine & Norepinephrine): Enhance fight-or-flight response.

Question 14

pancreatic hormones

Answer 14

Pancreatic Hormones:

Insulin: Lowers blood glucose levels.
Glucagon: Raises blood glucose levels.

Question 15

Explain the relationship
between the hypothalamus and pituitary gland.

Answer 15

Structure and Connection: The pituitary gland, located at the base of the brain, is connected to the hypothalamus by the infundibulum (a stalk). The pituitary has two parts: the anterior and posterior lobes.

Posterior Pituitary: This part stores and releases hormones produced by the hypothalamus, such as oxytocin and antidiuretic hormone (ADH). These hormones travel down the hypothalamic-hypophyseal tract to the posterior pituitary, where they are released into the bloodstream.

Anterior Pituitary: The hypothalamus regulates this lobe by releasing hormones into the hypophyseal portal system, a network of blood vessels. These hormones stimulate or inhibit the release of hormones from the anterior pituitary, affecting various bodily functions.

Question 16

Erythropoiesis

Answer 16

Erythropoiesis is the process of producing red blood cells (erythrocytes) in the body. It begins with hematopoietic stem cells in the red bone marrow, which transform into proerythroblasts and then undergo several stages, eventually becoming reticulocytes. These reticulocytes mature into erythrocytes, which are crucial for oxygen transport in the blood.

Question 17

Erythropoietin (EPO)

Answer 17

Erythropoietin (EPO) is a hormone that regulates erythropoiesis. It is primarily produced by the kidneys and, to a lesser extent, the liver. When oxygen levels in the blood drop (hypoxia), the kidneys release more EPO, stimulating the bone marrow to produce more red blood cells. This process helps restore normal oxygen levels in the blood.

Question 18

Components of Blood of blood

Answer 18

Plasma: This is the liquid part of blood, making up about 55% of its total volume. Plasma is a straw-colored, viscous fluid that is 90% water. It contains over 100 different dissolved solutes, including nutrients, gases, hormones, wastes, proteins, and electrolytes. Plasma proteins such as albumin, globulins, and fibrinogen play crucial roles in maintaining osmotic pressure and blood clotting.

Question 19

Formed Elements of blood

Answer 19

These include erythrocytes (red blood cells), leukocytes (white blood cells), and platelets. Erythrocytes are the most numerous, responsible for oxygen transport. Leukocytes are involved in immune defense, and platelets are essential for blood clotting. Formed elements account for about 45% of blood volume.

Question 20

Typical pH of Whole Blood

Answer 20

The typical pH of whole blood is about , which is slightly alkaline. This pH level is crucial for maintaining proper physiological functions and enzyme activities in the body.

Question 21

Hematocrit of blood

Answer 21

As for hematocrit, it refers to the percentage of blood volume that is composed of red blood cells. Normal hematocrit values vary between genders: for healthy males, it is typically around , and for females, it is around . This measure is important for assessing the oxygen-carrying capacity of the blood. Understanding these values can help in diagnosing various health conditions related to blood composition.

Question 22

Neutrophils (Granulocytes)

Answer 22

Characteristics: Multilobed nucleus, inconspicuous granules. Function: Phagocytize bacteria. Lifespan: 6 hours to a few days.

Question 23

Eosinophils (Granulocytes)

Answer 23

Characteristics: Bilobed nucleus, red granules. Function: Attack parasitic worms, involved in allergy and asthma. Lifespan: About 5 days.

Question 24

Basophils (Granulocytes)

Answer 24

Characteristics: Bilobed nucleus, large purplish-black granules. Function: Release histamine for inflammation, contain heparin. Lifespan: A few hours to a few days.

Question 25

Lymphocytes (Agranulocytes)

Answer 25

Characteristics: Spherical or indented nucleus, pale blue cytoplasm. Function: Mount immune response via direct attack or antibodies. Lifespan: Hours to years.

Question 26

Monocytes (Agranulocytes)

Answer 26

Characteristics: U or kidney-shaped nucleus, gray-blue cytoplasm. Function: Phagocytosis, develop into macrophages. Lifespan: Months.

Question 27

Describe the steps in the process of hemostasis.

Answer 27

Vascular Spasm: This is the immediate response to blood vessel injury. The smooth muscle in the vessel wall contracts, causing vasoconstriction, which reduces blood flow and limits blood loss. Platelet Plug Formation: When the endothelium (vessel lining) is damaged, underlying collagen fibers are exposed. Platelets adhere to these fibers and release chemicals that make nearby platelets sticky, forming a platelet plug. Coagulation (Blood Clotting): This step reinforces the platelet plug with fibrin threads, creating a stable clot. Coagulation involves a cascade of reactions that convert prothrombin to thrombin, which then transforms fibrinogen into fibrin, forming a mesh that traps blood cells and platelets.

Question 28

Platelets function

Answer 28

Function: Platelets are crucial in hemostasis, the process that stops bleeding. They aggregate at the site of a blood vessel injury, forming a temporary plug. This action is part of a positive feedback loop where platelets release chemicals to attract more platelets, enhancing the clotting process.

Question 29

Thrombin function

Answer 29

Function: Thrombin is an enzyme that plays a central role in the coagulation cascade. It converts fibrinogen, a soluble plasma protein, into fibrin, an insoluble protein that forms the structural basis of a blood clot.

Question 30

Fibrin function

Answer 30

Function: Fibrin forms a mesh that traps blood cells, effectively sealing the wound and providing a stable structure for the clot.

Question 31

Describe the 3 layers of the heart wall and pericardium.

Answer 31

Epicardium: This is the outermost layer and is also known as the visceral layer of the serous pericardium. It often contains fat, especially in older individuals. Myocardium: The middle layer, composed mainly of cardiac muscle, forms the bulk of the heart. This layer is responsible for the heart's contractile function. The cardiac muscle cells are arranged in spiral or circular bundles, which help in the effective contraction of the heart. Endocardium: The innermost layer, a glistening white sheet of endothelium, lines the heart chambers and covers the heart valves.

Question 32

Pericardium

Answer 32

The heart is enclosed in a double-walled sac called the pericardium, which consists of: Fibrous Pericardium: A tough, dense connective tissue layer that protects the heart, anchors it to surrounding structures, and prevents overfilling. Serous Pericardium: A thin, slippery membrane with two layers: Parietal Layer: Lines the internal surface of the fibrous pericardium. Visceral Layer (Epicardium): Covers the heart surface.

Question 33

Pathway of Blood

Answer 33

Oxygen-Poor Blood Entry: Blood enters the heart through the superior vena cava, inferior vena cava, and coronary sinus into the right atrium. It passes through the tricuspid valve into the right ventricle. Pulmonary Circuit: Blood is pumped through the pulmonary semilunar valve into the pulmonary trunk and then into the pulmonary arteries. It travels to the lungs to be oxygenated. Oxygen-Rich Blood Return: Oxygen-rich blood returns to the heart via the four pulmonary veins into the left atrium. It passes through the mitral valve into the left ventricle. Systemic Circuit: Blood is pumped through the aortic semilunar valve into the aorta. It is delivered to body tissues, and oxygen-poor blood returns to the heart. Heart Valves and Their Functions Atrioventricular Valves: Located between the atria and ventricles, these include the tricuspid (right) and mitral (left) valves. They prevent backflow into the atria when ventricles contract. Semilunar Valves: Located at the junction of the ventricles and arteries, these include the pulmonary and aortic valves. They prevent backflow into the ventricles after blood is ejected. These valves ensure unidirectional blood flow, opening and closing in response to pressure changes.

Question 34

Pacemaker Cells

Answer 34

Pacemaker Potential: Begins with slow depolarization due to opening of Na⁺ channels and closing of K⁺ channels. The membrane potential gradually becomes more positive. Depolarization: Occurs when the pacemaker potential reaches threshold (around -40 mV), primarily due to Ca²⁺ influx through Ca²⁺ channels, peaking at approximately +2 mV. Repolarization: Ca²⁺ channels inactivate, and K⁺ channels open, allowing K⁺ efflux, returning the membrane potential to its most negative voltage.

Question 35

contractile Cells

Answer 35

Depolarization: Initiated by Na⁺ influx through fast voltage-gated Na⁺ channels, rapidly depolarizing the membrane. Plateau Phase: Characterized by Ca²⁺ influx through slow Ca²⁺ channels, maintaining depolarization as most K⁺ channels remain closed. Repolarization: Ca²⁺ channels inactivate, and K⁺ channels open, allowing K⁺ efflux, restoring the resting membrane potential.

Question 36

Intrinsic Conduction System

Answer 36

The intrinsic conduction system of the heart is responsible for initiating and coordinating the heartbeat. It includes: Sinoatrial (SA) Node: Located in the right atrium, it sets the pace for the heart, typically generating impulses about 75 times per minute. Atrioventricular (AV) Node: Delays the impulse to allow the atria to contract before the ventricles. Atrioventricular (AV) Bundle: Conducts impulses through the interventricular septum. Bundle Branches: Carry impulses toward the heart apex. Purkinje Fibers: Depolarize the contractile cells of the ventricles.

Question 37

ecg waves and intervals

Answer 37

ECG Waves and Intervals: P Wave: Atrial depolarization initiated by the SA node. QRS Complex: Ventricular depolarization, causing ventricular contraction. T Wave: Ventricular repolarization. P-R Interval: Time from the start of atrial depolarization to the start of ventricular depolarizatio

Question 38

Ventricular Filling Phase phases the cardiac cycle to a line grap

Answer 38

Pressure: Low in ventricles; atrial pressure slightly higher. Volume: Increases as blood fills the ventricles. ECG: P wave indicates atrial depolarization.

Question 39

Isovolumetric Contraction Phase phases the cardiac cycle to a line grap

Answer 39

Pressure: Rapid increase in ventricular pressure as ventricles contract. Volume: Remains constant as all valves are closed. ECG: QRS complex indicates ventricular depolarization.

Question 40

Ventricular Ejection Phase phases the cardiac cycle to a line grap

Answer 40

Pressure: Peaks and then decreases as blood is ejected. Volume: Decreases as blood leaves the ventricles. ECG: T wave indicates ventricular repolarization.

Question 41

Isovolumetric Relaxation Phase

Answer 41

Pressure: Falls as ventricles relax. Volume: Remains constant as all valves are closed.

Question 42

Stroke Volume (SV)

Answer 42

Preload: The stretch of cardiac muscle fibers before contraction, influenced by venous return. Increased preload enhances SV. Contractility: Enhanced by hormones like epinephrine and thyroxine, and ions such as calcium, which increase muscle contraction strength. Afterload: The pressure the heart must overcome to eject blood. High afterload can reduce SV.

Question 43

heart rate

Answer 43

Heart Rate (HR): Autonomic Nervous System: Sympathetic activation increases HR and contractility, while parasympathetic activation decreases HR. Chemical Factors: Hormones and ions can alter HR. For example, epinephrine increases HR. Regulation of Cardiac Output: The autonomic nervous system regulates CO by adjusting HR and SV in response to physical demands, stress, or changes in blood pressure. Sympathetic stimulation increases HR and contractility, enhancing CO, while parasympathetic activity reduces HR. Additionally, factors like exercise, body temperature, and age can influence HR and, consequently, CO. This dynamic regulation allows the heart to meet varying physiological demands efficiently.**

Question 44

Graves’ Disease

Answer 44

Graves' disease is an autoimmune disorder where abnormal antibodies mimic TSH, leading to excessive thyroid hormone release. Symptoms include a high metabolic rate, sweating, rapid heartbeat, nervousness, and weight loss. A notable feature is exophthalmos, where the eyes protrude due to tissue swelling behind them. Treatments involve thyroid gland removal or radioactive iodine therapy to destroy active thyroid cells [1].

Question 45

Addison’s Disease

Answer 45

This condition involves insufficient production of glucocorticoids and mineralocorticoids by the adrenal cortex. Symptoms include weight loss, low blood glucose and sodium levels, high potassium levels, dehydration, and hypotension. A characteristic sign is skin bronzing due to increased ACTH levels. Treatment typically involves corticosteroid replacement therapy [2].

Question 46

Diabetes Mellitus and Insipidus

Answer 46

Diabetes mellitus is characterized by high blood sugar levels due to insulin issues, while diabetes insipidus involves a deficiency in antidiuretic hormone, leading to excessive urination and thirst. Both require different management strategies.

Question 47

Dwarfism

Answer 47

Dwarfism results from insufficient growth hormone production, leading to short stature. It can be treated with growth hormone therapy if diagnosed early.

Question 48

Anemia

Answer 48

This condition occurs when the blood's oxygen-carrying capacity is too low, leading to fatigue, pallor, and shortness of breath. Causes include blood loss, insufficient red blood cell production, or excessive destruction of red blood cells. Treatments vary based on the cause, such as iron supplements for iron-deficiency anemia [1].

Question 49

Sickle-cell Anemia

Answer 49

Predominantly affecting those in malaria-prone regions, this genetic disorder causes red blood cells to sickle, reducing malaria parasite survival. Treatments include blood transfusions and new gene-editing therapies like CRISPR for a potential cure [1].

Question 50

Polycythemia

Answer 50

Characterized by an excess of red blood cells, this condition increases blood viscosity, impairing circulation. It can be treated by therapeutic phlebotomy to reduce blood volume [1].

Question 51

Hemophilia

Answer 51

A genetic disorder where blood doesn't clot properly due to missing clotting factors, leading to excessive bleeding [2].

Question 52

Transfusion Reactions

Answer 52

Occur when mismatched blood is transfused, causing the recipient's antibodies to attack donor red blood cells, leading to complications like kidney failure [3].

Question 53

Pericarditis

Answer 53

This is the inflammation of the pericardium, the protective sac around the heart. It can cause a creaking sound due to friction, and in severe cases, lead to cardiac tamponade, where fluid buildup compresses the heart, impairing its function [1].

Question 54

Stenosis

Answer 54

This refers to the narrowing of heart valves, which can restrict blood flow and lead to various complications.

Question 55

Myocardial Infarction

Answer 55

Commonly known as a heart attack, this occurs when blood flow to a part of the heart is blocked, causing damage to the heart muscle.

Question 56

Junctional Rhythm

Answer 56

This is a type of heart rhythm where the AV node takes over as the pacemaker, resulting in a slower heart rate than normal sinus rhythm [2].

Question 57

Heart Block

Answer 57

A condition where the electrical signals in the heart are partially or completely blocked, affecting the heart's ability to pump effectively.

Question 58

Congestive Heart Failure

Answer 58

This is when the heart is unable to pump blood efficiently, leading to fluid buildup in the lungs and other parts of the body.

Question 59

Congenital Heart Defect

Answer 59

These are structural problems with the heart present from birth, affecting its normal function.