Unit #4: Cardiovascular, Lymphatic, Immunity, and Respiratory Systems

Flashcards covering key learning objectives from Unit #4: Cardiovascular System (Parts I & II), Lymphatic System, Immunity, and Respiratory System.

What are the four primary functions of blood?

Transportation (dissolved gases, nutrients, wastes, hormones), Regulation (body temperature, pH, and fluid balance), Protection (fighting infections and diseases), and Clotting (preventing excessive blood loss from damaged vessels).

What are the three formed elements (cells) found in blood?

Erythrocytes (red blood cells), Leukocytes (white blood cells), and Platelets (thrombocytes).

What major substances are found in blood plasma?

Plasma proteins (albumins, globulins, fibrinogen), electrolytes, nutrients/wastes, gases, and hormones.

What is the function of an erythrocyte?

To transport oxygen from the lungs to the body's tissues and carry some carbon dioxide back to the lungs.

How many erythrocytes are typically present in a microliter of blood?

$4\text{--}6\text{ million}$ red blood cells per microliter.

What is the function of hemoglobin and where is it located?

Hemoglobin binds to oxygen, transports it throughout the body, and carries some carbon dioxide; it is located inside red blood cells.

What is anemia and why does it lower oxygen-carrying capacity?

Anemia is a condition where the blood has too few healthy red blood cells or too little hemoglobin, which reduces the amount of oxygen the blood can carry.

What is the primary function of leukocytes?

They protect the body against infections and diseases by fighting bacteria, viruses, and other harmful substances.

What terms describe having too few or too many circulating leukocytes?

Leukopenia refers to having too few white blood cells, and leukocytosis refers to having too many white blood cells.

How many leukocytes are found in a microliter of blood?

$4{,}500\text{--}11{,}000$ white blood cells per microliter.

What is the function and normal count of platelets per microliter of blood?

Platelets help blood clot by gathering at damaged blood vessels to form a platelet plug; there are $150{,}000\text{--}400{,}000$ platelets per microliter.

What antibodies are produced by each ABO blood type?

Type A produces anti-B antibodies; Type B produces anti-A antibodies; Type AB produces neither antibody; Type O produces both anti-A and anti-B antibodies.

What blood types can safely be transfused into an $O^+$ patient?

$O^+$ and $O^-$.

What blood types can safely be transfused into an $AB^-$ patient?

$AB^-$, $A^-$, $B^-$, and $O^-$.

In which body cavity is the heart located, and what is the function of the pericardium?

The heart is located in the thoracic cavity; the pericardium provides protection, especially from friction.

What is the step-by-step pathway of deoxygenated blood through the heart to the pulmonary capillaries?

Superior/Inferior vena cava $\rightarrow$ Right atrium $\rightarrow$ Tricuspid valve $\rightarrow$ Right ventricle $\rightarrow$ Pulmonary semilunar valve $\rightarrow$ Pulmonary trunk $\rightarrow$ Right/Left pulmonary arteries $\rightarrow$ Pulmonary arterioles $\rightarrow$ Pulmonary capillaries (where blood releases $CO_2$ and picks up $O_2$).

What is the pathway of oxygenated blood from the pulmonary capillaries to the systemic circulation?

Pulmonary venules $\rightarrow$ Pulmonary veins $\rightarrow$ Left atrium $\rightarrow$ Mitral (bicuspid) valve $\rightarrow$ Left ventricle $\rightarrow$ Aortic semilunar valve $\rightarrow$ Aorta.

Which arteries supply oxygen-rich blood to the myocardium of the heart itself?

The right coronary artery and the left coronary artery (which branches into vessels such as the left anterior descending and left circumflex arteries).

What is a myocardial infarction and what causes it?

A heart attack caused by a blockage that prevents oxygen-rich blood from reaching the heart muscle, leading to heart tissue death.

What are the structural functions of arteries, veins, and capillaries?

Arteries carry blood away from the heart; veins carry blood to the heart; capillaries serve as exchange vessels between arteries and veins.

What occurs during systole versus diastole?

Systole is the contraction of the heart (atrial or ventricular systole), whereas diastole is the relaxation of the heart and its filling with blood (atrial or ventricular diastole).

What causes the 'Lubb' and 'Dubb' sounds of the heart?

'LUBB' is heard at the beginning of ventricular systole when the atrioventricular (AV) valves close; 'DUBB' is heard at the beginning of ventricular diastole when the semilunar valves close.

What causes striations in cardiac muscle cells, and what is the role of intercalated disks?

Striations are caused by actin (thin) and myosin (thick) filaments; intercalated disks connect and allow the heart muscle fibers to contract as one unit.

What is the sequence of electrical impulse conduction through the heart?

Sinoatrial (SA) node $\rightarrow$ Atrioventricular (AV) node (which briefly delays the impulse) $\rightarrow$ AV bundle and Purkinje fibers.

What electrical events in the heart correspond to the P wave, QRS complex, and T wave on an ECG?

P wave: atrial depolarization; QRS complex: ventricular depolarization; T wave: ventricular repolarization.

Why is atrial repolarization not seen as a distinct wave on an ECG?

It is hidden by the much larger QRS complex, which represents ventricular depolarization.

How do tachycardia, bradycardia, and fibrillation differ?

Tachycardia is a heart rate that is too fast; bradycardia is a heart rate that is too slow; fibrillation is when the heart muscle quivers instead of contracting normally.

How do the sympathetic and parasympathetic nervous systems affect heart rate?

The sympathetic system stimulates the SA node, AV node, and myocardium to increase heart rate and contraction strength; the parasympathetic system sends continuous impulses to the SA and AV nodes to slow the heart rate (acting as a 'brake').

What factors cause an increase in blood pressure?

An increase in heart rate, an increase in blood volume, an increase in peripheral resistance, an increase in blood viscosity, and a loss of arterial elasticity (hardening of the arteries).

What are the three primary functions of the lymphatic system?

Fluid balance (collects excess tissue fluid and returns it to the bloodstream), Fat absorption (absorbs and transports fats and fat-soluble vitamins from the small intestine), and Immune defense (filters harmful substances and produces/transports immune cells).

What are the specific functions of the thymus, lymph nodes, tonsils, and spleen?

Thymus: makes and trains T cells; Lymph nodes: filter lymph for harmful substances or cells; Tonsils: filter out germs entering through the nose or mouth; Spleen: stores and filters blood and makes white blood cells.

What is lymphedema?

Swelling caused by fluid buildup (resulting in puffy skin, joint mobility issues, pain, and discomfort) due to a damaged, blocked, or missing lymphatic vessel.

What is the difference between a nonspecific (innate) defense and a specific defense?

Nonspecific defenses are general mechanisms that protect against many types of pathogens, whereas specific defenses are precise mechanisms that target specific pathogens.

What are the six nonspecific/innate defenses of the body?

Species resistance, Mechanical barriers (e.g., skin), Chemical barriers (e.g., stomach acid, lysozyme), Fevers, Inflammation, and Phagocytosis (e.g., macrophages, neutrophils).

How do T cells and B cells function differently in an immune response?

T cells directly attack foreign antigens, whereas B cells produce antibodies against foreign antigens.

How does a primary immune response differ from a secondary immune response?

A primary response occurs on first encounter when B and T cells are activated and release antibodies; a secondary response occurs upon re-encountering the same antigen, where memory B and T cells rapidly produce antibodies.

What is the difference between active and passive immunity?

Active immunity is developed after exposure to an infection or from getting a vaccine; passive immunity is acquired from someone or something else.

What are clinical examples of naturally acquired passive immunity and artificially acquired passive immunity?

Naturally acquired passive immunity occurs when a fetus acquires antibodies from the mother; artificially acquired passive immunity occurs through the injection of antibodies produced by someone else.

What are the four events of respiration?

Ventilation (air moving in and out of lungs), External respiration (gas exchange between lungs and blood), Internal respiration (gas exchange between blood and tissues), and Cellular respiration (cells using $O_2$ to free energy/ATP from glucose).

What is the complete pathway of air from the nostrils to the alveoli?

Nostrils (nares) $\rightarrow$ Nasal cavity $\rightarrow$ Pharynx $\rightarrow$ Larynx $\rightarrow$ Trachea $\rightarrow$ Primary bronchi $\rightarrow$ Secondary bronchi $\rightarrow$ Tertiary bronchi $\rightarrow$ Bronchioles $\rightarrow$ Alveolar ducts $\rightarrow$ Alveolar sacs $\rightarrow$ Alveoli.

What is the function of the C-shaped cartilage rings surrounding the trachea?

They keep the trachea open for airflow and provide rigid support to prevent airway collapse, while leaving a flexible posterior gap that allows the esophagus to expand during swallowing.

What is the function of surfactant in the alveoli?

It reduces surface tension at the air-liquid interface to prevent alveolar collapse.

How do changes in thoracic volume and pressure drive inhalation and exhalation?

During inhalation, the diaphragm contracts and moves downward, increasing lung volume and decreasing intrapulmonic pressure, causing air to enter; during exhalation, the diaphragm relaxes and moves upward, decreasing lung volume and increasing pressure, forcing air out.

What are the two ways oxygen is transported in the blood?

$2\%$ is carried dissolved in plasma, and $98\%$ is carried bound to the heme groups of hemoglobin.

What are the three ways carbon dioxide is transported in the blood?

$10\%$ is carried dissolved in plasma, $20\%$ is carried bound to the amino groups of hemoglobin, and $70\%$ is carried as bicarbonate ions ($HCO_3^-$).

What causes respiratory acidosis and respiratory alkalosis?

Respiratory acidosis is caused by hypoventilation (too slow/shallow breathing), leading to excess $H^+$ and lower pH; respiratory alkalosis is caused by hyperventilation (increased rate/depth of breathing), leading to too little $H^+$ and higher pH.

Which brain regions contain centers that control the rate and depth of respiration?

The medulla oblongata and the pons.

How do the sympathetic and parasympathetic nervous systems affect the respiratory tract?

The sympathetic system causes bronchodilation and an increase in respiratory rate and depth; the parasympathetic system causes bronchoconstriction and a decrease in respiratory rate and depth.

What respiratory conditions are characterized by the breakdown of alveolar walls versus excessive mucus clogging airways?

Emphysema is characterized by the destruction and breakdown of alveolar walls with loss of elasticity; cystic fibrosis is a genetic disorder causing excessive thick mucus production that clogs airways.

In a blood pressure reading of 118/74, which value represents systolic pressure and what does it measure?

118 is the systolic pressure; it represents the pressure exerted on the arterial walls when the heart is contracting and forcing blood into the arteries.