Cerebral Blood Flow, Cardiovascular Function, and Haematology Practice Flashcards

Comprehensive practice flashcards covering cerebral/coronary blood flow, blood pressure regulation, capillary exchange mechanisms, lymphatic system function, and haematology including blood types and coagulation.

What is the Mean Arterial Pressure (MAP) range within which autoregulation maintains a stable Cerebral Blood Flow (CBF)?

$$60-160\,mmHg$$

How do metabolic factors such as carbon dioxide ($CO_2$) and hydrogen ions ($H^+$) regulate blood flow to active brain regions?

Increased levels of $CO_2$ and $H^+$ cause vasodilation, which increases blood flow to those regions.

What is the primary Myogenic response in cerebral autoregulation when blood pressure increases?

Increased blood pressure causes vessel stretch, which triggers vasoconstriction to ensure pressure-flow stability.

What are the two major baroreceptor locations involved in the reflex maintaining stable blood pressure?

The carotid sinuses and the aortic arch.

What is the physiological result of increased baroreceptor firing in response to high blood pressure?

It leads to a decrease in sympathetic output (reduced NE) and an increase in parasympathetic output (increased ACh), resulting in vasodilation, decreased heart rate, and decreased contractility to lower blood pressure.

How is hypertension typically defined numerically according to the transcript?

Chronically elevated blood pressure typically greater than $140/90\,mmHg$.

What is the equation for Cardiac Output ($CO$)?

$CO = HR \times SV$ (where $HR$ is Heart Rate and $SV$ is Stroke Volume).

What is the function of the hormone Atrial Natriuretic Peptide (ANP) in blood pressure regulation?

It promotes vasodilation and sodium excretion to decrease blood pressure.

Which capillary type is found in the kidneys and small intestine, characterized by endothelial cells with pores?

Fenestrated capillaries.

Which capillary type is characterized by large gaps between endothelial cells and is found in the liver, bone marrow, and spleen?

Sinusoidal (Discontinuous) capillaries.

What is Starling’s Law of Capillaries represented as an equation for Net Filtration Pressure ($NFP$)?

$NFP = (P_c - P_{if}) - (\pi_c - \pi_{if})$ (where $P_c$ is capillary hydrostatic pressure, $P_{if}$ is interstitial hydrostatic pressure, $\pi_c$ is capillary oncotic pressure, and $\pi_{if}$ is interstitial oncotic pressure).

According to the Principle of Continuity, what is the relationship between cross-sectional area ($A$) and velocity ($v$)?

$Q = A \times v$; as the total cross-sectional area increases (as in capillaries), the velocity of blood flow decreases.

What is the criteria for diagnosing Orthostatic Hypotension (OH) upon standing?

A blood pressure drop of $\ge 20\,mmHg$ systolic or $\ge 10\,mmHg$ diastolic within $1-3\text{ minutes}$ of standing.

Which inflammatory marker produced by the liver is used as a sensitive test for cardiovascular disease (CVD) risk?

C-Reactive Protein (CRP), specifically the hs-CRP test.

What are the average volume and normal pH range of blood in an adult?

Average volume is approximately $5\,L$ and the pH range is $7.35-7.45$.

What are the four major types of plasma proteins and their primary sources?

Albumins, Globulins, Fibrinogen, and Transferrin; they are primarily produced by the liver (though globulins are also produced by immune cells).

Which white blood cell type is characterized as 'first responders' that phagocytose bacteria and fungi?

Neutrophils ($50-70 \% \text{ of WBCs}$).

What is the primary site and regulatory hormone for erythropoiesis (red blood cell formation)?

The bone marrow; regulated by Erythropoietin (EPO), which is produced mainly by the kidneys in response to hypoxia.

What are the normal ranges for Hematocrit (Hct) in males and females?

Males: $40-54 \%$; Females: $37-47 \%$.

What is the lifespan of a mature erythrocyte and where is it primarily removed from circulation?

Approximately $120\,days$; removed by macrophages in the spleen and liver.

What is the name of the hormone that regulates the production of platelets (thrombopoiesis) and where is it mainly produced?

Thrombopoietin (TPO); produced mainly by the liver.

What are the four steps of hemostasis to stop blood loss after vascular injury?

1. Vasoconstriction; 2. Platelet Plug Formation; 3. Coagulation Cascade and Clot Formation; 4. Tissue Repair.

Which pathway of the coagulation cascade is triggered by external trauma exposing Tissue Factor (Factor III)?

The Extrinsic Pathway.

What is the role of plasmin in the process of fibrinolysis?

Plasmin is the enzyme that digests fibrin to dissolve clots and restore normal blood flow.

Which blood type is known as the universal donor and why?

Type O; because it lacks A and B antigens (agglutinogens) on the surface of the red blood cells.

What is the clinical significance of a positive Net Filtration Pressure ($NFP$) at the arterial end of a capillary?

A positive $NFP$ indicates that filtration dominates, meaning fluid moves out of the capillary into the interstitial space.

How does chronic hypertension affect the baroreceptor reflex?

Baroreceptors adapt or "reset" to a higher baseline, which reduces their sensitivity to elevated blood pressure.

What are the five stages of atherosclerosis development?

1. Endothelial injury; 2. Lipid accumulation & oxidation; 3. Inflammatory response (monocytes to foam cells); 4. Plaque formation (fibrous cap); 5. Plaque progression & complications (rupture/thrombosis).