Week 6 – Blood, ECG, and Blood Typing

Question–answer flashcards covering blood composition, hematologic tests, leukocytes, hemostasis, blood typing, cardiac conduction, ECG interpretation, pulse, and blood-pressure measurement for Physiology Lab Week 6.

Approximately how many mL of blood per kilogram of body weight does an average adult possess?

About 79 mL/kg (± 10 %) of body weight.

What is the typical total blood volume range for adult females and males?

Females: 4–5 L; Males: 5–6 L.

What percentage of whole blood is plasma?

Roughly 55 % of whole blood.

What percent of plasma is water?

≈ 90 % is H₂O.

Name the three main plasma proteins and one key function for each.

Albumin – osmotic pressure; Fibrinogen – clotting; Globulins – antibodies & transport.

What percentage of whole blood is made up of formed elements?

About 45 %.

What is the primary function of red blood cells (RBCs)?

Transport of O₂ and CO₂.

Define hematocrit.

The proportion (%) of RBCs in whole blood.

Normal hematocrit values for males and females are approximately and , respectively.

46.2 % for males and 40.6 % for females.

What condition is indicated by a depressed hematocrit?

Anemia.

What condition is indicated by an elevated hematocrit?

Polycythemia.

List the two major classes of leukocytes and a basic distinguishing feature.

Granulocytes – visible granules & multilobed nuclei; Agranulocytes – lack obvious granules.

Which leukocyte is most abundant and is associated with acute bacterial infection?

Neutrophils (50–70 %).

Which leukocyte defends against parasitic worms and is elevated in allergies?

Eosinophils.

Which leukocyte mediates allergic reactions similar to mast cells?

Basophils.

Monocytes differentiate into what cell type once in tissues?

Macrophages.

Which leukocyte group is chiefly responsible for specific immune responses and antibody production?

Lymphocytes.

Describe the origin and basic role of platelets.

Produced from megakaryocytes in red bone marrow; initiate hemostasis by forming platelet plugs.

Outline the sequence leading to a platelet plug formation after vessel injury.

Exposed subendothelium → ADP binding → platelet activation → stickiness → aggregation → hemostatic plug.

What test gives the total number of RBCs or WBCs per volume of blood?

Total RBC/WBC count.

Define leukocytosis and give one common cause.

WBC count > 10,000/mm³; often due to infection or inflammation.

Define leukopenia and state one possible cause.

WBC count < 4,000/mm³; may result from chemotherapy, sepsis, or aplastic anemia.

Which five questions are asked during basic conduction & rhythm analysis of an ECG?

1) P waves present? 2) QRS after each P? 3) PR < 0.20 s? 4) QRS ≤ 0.10 s? 5) HR 60–100 bpm? 6) Rhythm regular?

Name the normal adult heart rhythm that meets all six conduction criteria.

Normal sinus rhythm.

What does the P wave represent on an ECG?

Atrial depolarization.

What is the normal PR interval duration?

Less than 0.20 seconds.

Which autonomic nerves provide parasympathetic and sympathetic input to the heart’s conduction system?

Parasympathetic – Vagus nerve; Sympathetic – thoracic spinal nerves T1–T5.

Trace the electrical conduction pathway through the heart.

SA node → AV node → Bundle of His → Right & Left bundle branches → Purkinje fibers.

List the three major steps of hemostasis.

1) Vasoconstriction, 2) Platelet plug formation, 3) Coagulation (fibrin clot).

Normal bleeding time assesses __ function and is _____ to _____ minutes.

Platelet function; 3–10 minutes.

Normal coagulation time assesses __ function and is _____ to _____ seconds.

Coagulation factor function; 11–15 seconds.

On what basis are the ABO blood groups determined?

Presence or absence of A and/or B antigens on RBCs.

Which blood type is the universal donor of red blood cells?

Type O (especially O–).

Which blood type is the universal recipient of red blood cells?

Type AB (especially AB+).

Why must Rh-negative patients receive Rh-negative blood?

Exposure to Rh antigen (D) can cause anti-D IgG formation leading to hemolytic reactions.

What treatment is given to Rh-negative mothers to prevent hemolytic disease of the newborn?

RhoGAM (anti-D immunoglobulin).

State the normal adult pulse rate range.

60–100 beats per minute.

During sphygmomanometry, the first audible Korotkoff sound corresponds to what pressure?

Systolic blood pressure.

At what point is diastolic pressure recorded during blood pressure measurement?

When Korotkoff sounds disappear as cuff pressure falls below diastolic pressure.

Which six limb leads make up the frontal plane of a 12-lead ECG?

Leads I, II, III, aVR, aVL, aVF.

What mnemonic helps recall the normal order of WBC percentages?

‘Never Let Monkeys Eat Bananas’ – Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils.

Give the normal percentage range for lymphocytes in a differential count.

Approximately 25–33 % of total WBCs.