Anatomy #4 Exam

Formed Elements

45% of blood

Erythrocytes

99%, transport respiratory gases

Leukocytes

Platelets

Plasma

55% blood, contains water, proteins

and dissolved solutes, formed elements are suspended in plasma

Erythrocytes

Function: transport 02 and C02, lacks nuclei and organelles- carry gases more effectively

Leukocytes

Function: helps initiate an immune response and defend the body against pathogens, cantina nucleus and organelles, least abundant, but can’t live without them, motile and flexible- move within the interstitial fluid, most found in tissue vs. blood

Platelets

Help with blood clotting

What formed elements are found in the buffy coat?

Leukocytes and platelets (

What are the three functions of blood?

Transportation, Regulation, Regulates fluid distribution, Protection

Transportation

O2, CO2, nutrients, metabolic wastes, hormones, heat

Regulation

regulates body temperature, plasma absorbs and distributes heat, then blood vessels dilate and constrict depending on need, regulates pH levels through buffers

Regulates fluid distribution

the constant exchange between blood plasma and interstitial fluid, if too much fluid is absorbed into blood -> high BP, if too much fluid leaves the blood and enters tissue  drop in BP, and tissue swells

Protection

leukocytes help guard against infection by mounting immune response against pathogens or antigens, produce antibodies that bind to antigens until the immune system destroys them, platelets secrete factors that initiate blood clotting to prevent blood loss

Hematocrit

Percentage of the volume of all formed elements in the blood

Hematocrit

Values vary slightly and are dependent on age and sex, Young children may vary between 30-60%; then the range narrows to 35-50% as children get older, Men tend to have higher hematocrit-testosterone stimulates release of EPO, Women have monthly blood loss, Inverse relationships between hematocrit and body fat

Granulocytes

granules in cytoplasm, visible in microscope

Agranulocytes

very small granules, not visible in microscope

Neutrophils

50-70%- most abundant, Multi-lobed (3-5) nuclei-interconnected by thin strands, Pale or neutral granules in the cytoplasm

Neutrophils

Phagocytize bacteria

Eosinophils

1-4%, Bilobed nuclei connected by a thin strand, Large reddish or pink-orange granules in the cytoplasm

Eosinophils

Phagocytize allergens and releases enzymes that attack parasites

Basophil

Basophils

Secretes Histamine and Heparin during allergic reaction

Histamine

Causes vasodilation to speed up blood flow to injured tissue

Heparin

anticoagulant to inhibit blood clotting

Lymphocytes

20-40%- 2nd most abundant, Most reside in lymphatic organs, Round, slightly indented, dark-violet nuclei, Thin rim of cytoplasm

Lymphocytes

Serve in immune memory for viruses

T-lymphocytes

direct an immune response, directly attack foreign cells and virus-infected cells

B-lymphocytes

Produce antibodies

Natural Killer Cell

Attack abnormal and infected tissues

Monocytes

2-8%- largest, Violet, kidney-shaped or C-shaped nuclei, Abundant cytoplasm, Leave bloodstream after 3 days to enter tissues and differentiate into macrophages

Monocytes

Phagocytize bacteria, cell fragments, dead cells and debris

Anemia

caused by inadequate production of healthy erythrocytes or decreased survival of erythrocytes, body tissue can’t get enough O2, so the heart works harder. Symptoms: lethargy, SOB, pallor, fatigue, heart palpitations. Causes: chronic blood loss

Leukemia

malignancy of leukocyte forming cells, abnormal development and proliferation of leukocytes, malignant cells overtake red bone marrow and leave no room for normal cells

Pulmonary Circulation

sends deoxygenated blood from right side of heart to the lungs to pick up oxygen and drop off carbon dioxide then goes out through the left side of the heart. Blood vessels that take the blood to and from the lungs for gas exchange

Systemic Circulation

moves oxygenated blood from left side of the heart to the body’s (systemic) cells to drop off oxygen and pick up carbon dioxide and goes through the right side of the heart. Blood vessels that extend to all body regions

Blood Pressure

Blood is pulsing in arteries-consequence of ventricular contraction and relaxation, force per unit area that blood exerts against the inside wall of the vessel

Systolic BP

pressure in the artery during ventricular contraction (systole)- artery maximally stretched

Diastolic BP

pressure in artery during ventricular relaxation (diastole)- artery recoils no further

Epicardium (External)

The visceral layer of the pericardium, as we age more fat gets deposited here, and becomes thicker

Myocardium (Middle)

Composed of cardiac muscle, the thickest of the 3 layers, contracts/relaxes to pump blood

Endocardium (Internal)

Composed of simple squamous epithelial and areolar

Coronary Sulcus

groove that separates atria from ventricle

Anterior Interventricular Sulcus

grooves that extend from the coronary sulcus toward the apex of the heart (house blood vessels; drain from the heart)

Posterior Interventricular Sulcus

grooves that extend from the coronary sulcus toward the apex of the heart (house blood vessels; drain from the heart)

Right Atrium

received deoxygenated blood from SVC/IVC and coronary sinus

Right Ventricle

receives deoxygenated blood from the right atrium and pumps into pulmonary trunk

Left Atrium

receives oxygenated blood from pulmonary veins

Left Ventricle

receives oxygenated blood from the left atrium and pumps into aorta

Atrioventricular valves (AV)

cusps that keep blood flowing in one direction by preventing its backflow

Tricuspid Valve

prevents backflow of blood into R. Atrium

Mitral Valve

prevents backflow of blood into L. Atrium

Aortic Semilunar Valve

prevents backflow of blood into L. Ventricle

Superior vena cava

drains deoxygenated blood from head, neck, upper limbs, and superior trunk to right atrium

Inferior Vena Cava

drains deoxygenated blood from lower limbs and trunk into right atrium

Pulmonary Trunk

conducts deoxygenated blood from the right ventricle into pulmonary circulation (lungs); divides into right and left pulmonary arteries-carry deoxygenated blood to lungs

Pulmonary Veins

carry oxygenated blood from the lungs back to the heart

Aorta

Conducts oxygenated blood from the left ventricle into system circulation (body cells)

Chordae Tendineae

thin strands of collagen fibers that attach to the AV valves to prevent the valves from inverting

Papillary Muscles

cone-shaped muscular projections that anchor chordae tendineae

Interatrial Septum

thin wall between right and left atrium

Interventricular Septum

thick wall between right and left ventricles

Coronary Sinus

large vein that lies in the posterior coronary sulcus, drains deoxygenated blood into the right atrium

**FLOW OF BLOOD THROUGH THE HEART**

Deoxygenated blood → superior/inferior vena cava → right atrium→ tricuspid valve → right ventricle → pulmonary semilunar valve → pulmonary trunk → right/left pulmonary arteries → lungs (drops off CO2/ picks up O2) → Oxygenated blood → comes back to the heart via right/left pulmonary veins → left atrium → mitral valve → left ventricle → aortic semilunar valve → aorta → body cells ( dropping off O2/ picks up CO2) → Repeat

Sinoatrial Node (SA)

located in right atrium; “pacemaker”

Atrioventricular Node (AV)

located in floor of right atrium, near tricuspid valve, slows conduction of impulse from atria to ventricles to delay contraction from atria to ventricles

Atrioventricular Bundle

receives signals from AV node and travels through interventricular septum

Purkinje Fibers

processes that arise from bundles at the apex and spread throughout ventricles

Pericarditis

inflammation of the pericardium, caused by viruses, bacteria, or fungi, blood vessels become “leaky” and fluid accumulates in pericardial cavity, excess fluid can limit the heart’s movement and prevent chambers from filling with blood

Cardiomegaly

increased thickens of heart muscle wall (hypertrophy) or obvious increase in size (dilation) due to stress applied to heart. Undetected cause sudden death

Atherosclerosis

coronary arteries become narrowed and occluded with plaque

Angina Pectoris

poorly, localized pain in left chest, left arm/shoulder, sometimes the jaw and back

Myocardial Infarction (MI)

potentially lethal condition resulting from sudden and complete occlusion of a coronary vessels to supply blood

Arteries

convey blood away from heart to capillaries

Capillaries

exchange of substances between blood and tissues

Veins

drain blood from capillaries, transporting back to the heart

Venules

smallest veins, companion vessels with arterioles, postcapillary venules drain blood from capillaries

Arteries

efferent vessels, branch into smaller and smaller vessels

Veins

afferent vessels, become progressively larger as they merge and come closer to the heart

End Arteries

provide only one pathway to supply blood to the organ (splenic artery or renal artery)

Anastomoses

the site where two or more arteries or veins converge to supply the same body region

Arterial Anastomoses

provide alternative blood supply routes to body tissues or organs

Venous Anastomoses

provide several drainage routes for blood from same body regions (more common)

Tunica Intima

simple squamous epithelium, provides smooth surface- repels blood cells and platelets

Tunica Media

smooth muscle in circular layers, provides vasomotion-changes in diameter of blood vessel

Tunica Externa

areolar tissue with elastic and collagen fibers, anchors the vessel to other structures

Elastic Arteries

largest, conduct blood from heart to muscular arteries, abundant elastic fibers, allow stretch- when blood ejected from heart, allow to recoil-propels (aorta, pulmonary trunk)

Muscular Arteries

Distribute blood to specific body regions and organs (brachial artery, radial artery)

Arterioles

smallest arteries, regulate blood pressure and blood flow to different areas of the body through vasodilation and vasoconstriction

Precapillary Sphincters

Smooth muscle ring that controls blood flow at capillary origin

What are the functions of the precapillary sphincters

Relaxation and Contraction

Relaxation

Permits blood flow into the capillary bed to exchange with tissue fluid

Contraction

bypasses capillary bed and diverts blood flow to other tissues or organs

Continuous Capillaries

most common, endothelial cells form complete, continuous lining connected by tight junctions, materials pass through diffusion, found in muscles, skin, thymus, lungs, CNS

Fenestrated Capillaries

have fenestrations (pores), but basement membrane is still intact, found where a lot of fluid needs to transport between blood and interstitial tissue, found in small intestine, endocrine glands and kidneys

Sinusoids

larger gaps and discontinuous basement membrane, possess openings that allow the transport of larger materials (proteins, blood cells), found in bone marrow, anterior pituitary, parathyroid gland, adrenal gland, spleen, liver

Which vessels serve as blood reservoirs?

Veins

Blood Reservoirs (Veins)Reservoirs

Veins drain capillaries and return the blood to the heart. At rest, the body’s veins hold about 60% of the body’s blood

3 Mechanisms of venous return

Contains valves, skeletal muscle pump, respiratory pump