BIOL21B Exam 1 Study Guide Vocabulary

Comprehensive vocabulary flashcards covering Chapter 18 Blood, Chapter 19 Heart, Chapter 20 Blood Vessels, Chapter 21 Lymphatics, and related laboratory review topics for BIOL21B Exam 1.

Hematocrit

The percentage of whole blood volume occupied by erythrocytes.

Albumin

A major plasma protein that contributes to blood colloid osmotic pressure, helps retain water within the circulation, and transports substances such as fatty acids.

Erythropoietin (EPO)

A hormone produced mainly by the kidneys in adults that stimulates erythrocyte production in red bone marrow in response to reduced oxygen availability.

Reticulocytes

Immature erythrocytes recently released from red bone marrow whose count indicates the rate of erythrocyte production.

Polycythemia

An abnormally elevated erythrocyte concentration or hematocrit that increases blood viscosity and circulatory workload.

Diapedesis

The process by which leukocytes squeeze between endothelial cells of small vessels to enter tissue spaces.

Normal Arterial pH

The narrow physiological pH range of arterial blood, specified as $7.35\text{ to }7.45$.

Vascular Spasm

The initial stage of hemostasis in which an injured blood vessel constricts to reduce blood flow and limit blood loss.

Platelet Plug Formation

The second stage of hemostasis in which platelets adhere to a damaged vessel wall, become activated, and aggregate with additional platelets to form a temporary plug.

Coagulation

The third stage of hemostasis where thrombin converts soluble fibrinogen into insoluble fibrin to form a mesh that stabilizes a blood clot.

Epicardium

The outer layer of the heart wall, synonymous with the visceral layer of the serous pericardium.

Myocardium

The middle layer of the heart wall composed of cardiac muscle responsible for heart contraction.

Endocardium

The innermost layer of tissue lining the heart chambers and valves.

Sinoatrial (SA) Node

The primary cardiac pacemaker located in the right atrium near the superior vena cava that initiates electrical impulses.

Atrioventricular (AV) Node

A structure in the cardiac conduction system that delays conduction to allow atrial contraction to complete ventricular filling before ventricular activation.

P Wave

An ECG wave representing atrial depolarization.

QRS Complex

An ECG wave complex representing ventricular depolarization.

T Wave

An ECG wave representing ventricular repolarization.

Normal ECG Schematic

A graphical display of cardiac electrical activity illustrating the P wave, QRS complex, and T wave.

Isovolumetric Contraction

A ventricular phase during which pressure rises without blood ejection, both AV and semilunar valves are closed, and AV valve closure is associated with the S1 sound.

Isovolumetric Relaxation

A ventricular phase during which pressure falls without filling, both AV and semilunar valves are closed, and semilunar valve closure is associated with the S2 sound.

Stroke Volume (SV)

The volume of blood ejected per beat, calculated as $\text{SV} = \text{EDV} - \text{ESV}$.

Cardiac Output (CO)

The total volume of blood pumped by a ventricle per minute, calculated as $\text{CO} = \text{heart rate} \times \text{stroke volume}$.

Frank-Starling Response

The physiological mechanism where increased venous return increases filling and myocardial stretch, producing a stronger contraction and larger stroke volume.

Preload

The extent of myocardial stretch and filling of the ventricle prior to contraction.

Afterload

The pressure or arterial resistance that a ventricle must overcome to eject blood.

Tunica Intima

The innermost layer of a blood vessel wall, containing endothelium and a supporting basement membrane.

Tunica Media

The middle layer of a blood vessel wall containing smooth muscle and elastic tissue that alters vessel diameter.

Tunica Externa

The outer connective tissue layer of a blood vessel that supports and anchors the vessel.

Continuous Capillaries

Capillaries featuring a continuous endothelial lining and relatively restricted passage, found in muscle and many other tissues.

Fenestrated Capillaries

Capillaries containing pores that increase the passage of fluid and small solutes, found in the intestine and kidneys.

Sinusoidal Capillaries

Capillaries with large gaps and an incomplete basement membrane, located in the liver, spleen, and red bone marrow.

Pulse Pressure

The difference between systolic and diastolic blood pressure, calculated as $\text{Pulse pressure} = \text{systolic} - \text{diastolic}$.

Mean Arterial Pressure (MAP)

An estimated average pressure supporting tissue perfusion, calculated approximately as $\text{MAP} \approx \text{diastolic pressure} + \frac{1}{3} \times \text{pulse pressure}$.

Baroreceptors

Stretch receptors located in the carotid sinuses and aortic arch that detect changes in arterial blood pressure.

Renin

An enzyme released by the kidneys in response to reduced renal perfusion that converts angiotensinogen into angiotensin I.

Angiotensin-Converting Enzyme (ACE)

An enzyme present on vascular endothelium, especially in the lungs, that converts angiotensin I into angiotensin II.

Aldosterone

A hormone released by the adrenal cortex in response to angiotensin II that increases renal sodium reabsorption and water retention.

Atrial Natriuretic Peptide (ANP)

A hormone released in response to atrial stretch that promotes renal sodium excretion and water loss to reduce blood volume and pressure.

Lacteals

Specialized lymphatic capillaries in the small intestine that absorb dietary fats and transport them toward the bloodstream.

Thoracic Duct

The primary lymphatic duct that drains lymph from both lower limbs, the abdomen, left upper body, and left side of head and neck into venous blood.

Right Lymphatic Duct

The lymphatic duct that drains lymph from the right upper limb and right side of the head, neck, and thorax into venous blood.

Neutrophil

A granulocyte featuring a multi-lobed nucleus and fine granules whose primary role is phagocytosis of bacteria.

Eosinophil

A granulocyte usually possessing a two-lobed nucleus and prominent red-orange granules, involved in defense against parasites and allergic responses.

Basophil

A leukocyte containing dark granules that may obscure the nucleus, releasing chemical mediators of inflammation and allergy.

Monocyte

A large leukocyte characterized by an indented or kidney-shaped nucleus that can enter tissues and differentiate into macrophages.

Corrected Upper Limb Venous Pathway

A flowchart detailing blood flow through superficial and deep veins of the right upper limb as they unite to form the axillary, subclavian, and brachiocephalic veins.

Abdominal Venous Pathway

A schematic showing venous drainage from abdominal structures to the Inferior Vena Cava (IVC), contrasting direct right-sided drainage with left-sided drainage into the left renal vein.