System Physiology - Animal Blood and Circulation Flashcards

Comprehensive vocabulary flashcards covering blood composition, hematopoiesis, blood grouping, hemoglobin dynamics, hemostasis, and cardiac physiology based on the lecture notes.

Hematocrit (Packed Cell Volume - PCV)

The percentage of total blood volume occupied by $RBCs$, normally around $45\%$ for men and $40\%$ for women.

Erythrocytes ($RBCs$)

Biconcave discs of approximately $7.2\,\mu m$ in diameter that lack mitochondria and a nucleus to maximize gas exchange and flexibility.

Camelid RBCs

The unique oval/elliptical shape found in camels and llamas that prevents osmotic lysis and allows flow through viscous blood during dehydration.

Leukocytes ($WBCs$)

Nucleated, colorless cells involved in immune defense, categorized into granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (lymphocytes, monocytes).

Mnemonic: Never Let Monkeys Eat Bananas

A memory aid for the relative abundance of WBCs in peripheral blood: Neutrophils > Lymphocytes > Monocytes > Eosinophils > Basophils.

Forward Scatter (FSC)

A flow cytometry measurement correlated with cell size, where the order is Monocytes > Neutrophils > Lymphocytes.

Side Scatter (SSC)

A flow cytometry measurement correlated with cell granularity/internal complexity, being high for granulocytes and low for agranulocytes.

Thrombocytes (Platelets)

Anucleated cell fragments derived from giant bone marrow cells called megakaryocytes through endomitosis, crucial for hemostasis.

Hematopoietic Stem Cell (HSC)

A multipotent stem cell capable of self-renewal and differentiation, experimentally identified by markers $CD34^+$ and $CD38^-$.

Mesoblastic Phase

The first phase of haemopoiesis occurring in the yolk sac mesoderm from the $3rd$ week to the $3rd$ month of embryonic life.

Hepatic Phase

The phase of haemopoiesis from the $3rd$ month until birth where the liver is the chief site of blood cell production.

Myeloid Phase

The phase where red bone marrow becomes the exclusive site of blood production, starting from the $4th$ month of development.

Erythropoietin (EPO)

A glycoprotein hormone produced primarily by the kidney ($90\%$) and liver ($10\%$) that stimulates the production of red blood cells.

Plasma vs. Serum

Plasma contains water, proteins, and clotting factors like fibrinogen, whereas serum is plasma minus the clotting factors.

Albumin

The smallest and most abundant plasma protein, synthesized by the liver, which serves as the primary contributor to Blood Colloidal Osmotic Pressure ($BCOP$).

Gamma ($\gamma$) Globulins (Immunoglobulins)

Antibodies produced by plasma cells (not the liver) that function in adaptive immunity.

Kwashiorkor

A condition resulting from severe protein deficiency where a drop in albumin synthesis leads to decreased $BCOP$, causing massive swelling known as edema or ascites.

Renin-Angiotensin-Aldosterone System (RAAS)

A hormonal system triggered by low blood pressure that uses the vasoconstrictor Angiotensin II and the sodium-retaining hormone Aldosterone to increase blood volume.

Anti-Diuretic Hormone (ADH / Vasopressin)

A hormone that triggers the insertion of Aquaporin-$2$ ($AQP2$) channels in the kidney, resulting in the reabsorption of pure water to increase blood volume.

Atrial Natriuretic Peptide (ANP)

The 'anti-$RAAS$' hormone released by the heart atria that promotes the excretion of sodium ($Na^+$) and water to decrease blood volume.

Bombay Phenotype ($O_h$)

A rare genotype ($hh$) where the $H$ antigen is not produced, causing the individual to test as Type $O$ and possess Anti-$A$, Anti-$B$, and Anti-$H$ antibodies.

Hemolytic Disease of the Newborn (Erythroblastosis Fetalis)

A condition where an $Rh^-$ mother's antibodies cross the placenta and destroy the $RBCs$ of an $Rh^+$ fetus during a subsequent pregnancy.

Universal Donor

Type $O-$ blood because it lacks surface antigens $A$, $B$, and $Rh$, making it invisible to the recipient's antibodies.

Hemoglobin A (HbA)

The adult form of hemoglobin, a tetramer composed of $2$ alpha chains and $2$ beta chains with four heme groups containing $Fe^{2+}$.

Bohr Effect

The phenomenon where increasing $PCO_2$ and $H^+$ (lower pH) decreases hemoglobin's affinity for $O_2$, shifting the dissociation curve to the right.

Haldane Effect

The reciprocal of the Bohr effect, where the oxygenation of blood in the lungs promotes the release of $CO_2$.

CADET Shift

A mnemonic for factors that shift the oxygen-hemoglobin curve to the right: $CO_2$ increase, Acidosis, $DPG$ (2,3-$BPG$), Exercise, and Temperature increase.

Sickle Cell Anemia (HbS)

A genetic mutation where the $6th$ amino acid of the beta-globin chain changes from glutamic acid to valine, causing fiber polymerization and cell distortion.

Haemostasis

The localized sequence of physiological responses that stop bleeding, involving vascular spasm, platelet plug formation, and coagulation.

von Willebrand Factor (vWF)

A bridge molecule that allows platelets to bind to exposed subendothelial collagen during the adhesion phase of hemostasis.

Extrinsic Pathway

The coagulation pathway triggered by tissue trauma and mediated by Tissue Factor (Factor $III$).

Vitamin K

A vital cofactor for the gamma-glutamyl carboxylase enzyme, which activates clotting factors $II$, $VII$, $IX$, and $X$.

Foramen of Panizza

A unique anatomical shunt in crocodiles that allows blood to bypass the lungs during a dive by connecting the left and right aortic arches.

Sinoatrial (SA) Node

The primary pacemaker of the mammalian heart located in the right atrium, which sets the rhythm of electrical excitation.

Gap Junctions

Protein channels (connexins) in intercalated discs that allow for instant electrical coupling, creating a functional syncytium in the myocardium.

Calcium-Induced Calcium Release (CICR)

The mechanism in cardiac muscle where extracellular $Ca^{2+}$ entry via $L$-type channels triggers the release of more $Ca^{2+}$ from the sarcoplasmic reticulum.

Neurogenic Heart

A heart type found in arthropods where the beat is initiated by a nerve ganglion rather than the muscle itself.

Pacemaker Potential

The slow, spontaneous depolarization of pacemaker cells toward the threshold, driven by the funny current ($I_f$) through $HCN$ channels.

AV Nodal Delay

A pause of approximately $0.1\,s$ that allows the atria to finish contracting and fill the ventricles before ventricular systole begins.

Purkinje Fibers

The specialized ventricular conduction tissue with the fastest conduction velocity ($\approx 4.0\,m/s$) due to large diameter and high gap junction density.

P wave

The component of an $ECG$ that represents atrial depolarization initiated by the $SA$ node.

QRS complex

The component of an $ECG$ that represents rapid ventricular depolarization, masking atrial repolarization.

T wave

The component of an $ECG$ that represents ventricular repolarization.

Isovolumetric Contraction

A phase of the cardiac cycle when all four valves are closed and ventricular pressure rises while volume remains constant at End-Diastolic Volume ($EDV$).

Stroke Volume (SV)

The volume of blood ejected by one ventricle during a single contraction, calculated as $SV = EDV - ESV$.

Ejection Fraction (EF)

The percentage of $EDV$ pumped out during systole, where a value below $40\%$ is a hallmark of Congestive Heart Failure ($CHF$).

Preload

The degree of stretch on the myocardium before it contracts, which is directly proportional to stroke volume.

Frank-Starling Law of the Heart

The principle that the force of cardiac muscle contraction is directly proportional to the initial resting length of the muscle fibers.

Mean Arterial Pressure (MAP)

The average perfusion pressure driving blood through tissues, calculated as $MAP = DP + \frac{1}{3}(SP - DP)$.

Baroreceptor Reflex

A neural negative feedback loop that maintains blood pressure by sensing stretch in the carotid sinus and aortic arch.