BSC 2086 Exam 2 19-20

Tunica intima (tunica interna)

Innermost layer of blood vessel walls, composed of endothelium—simple squamous epithelium.

Tunica media

Middle layer of blood vessel walls, consisting of smooth muscle, collagen, and elastic tissue.

Tunica adventitia (tunica externa)

Outermost layer of blood vessel walls, made of loose connective tissue.

Vasa vasorum

Small vessels that supply blood to the outer half of the wall in larger vessels.

Elastic Arteries

Large conducting arteries such as the pulmonary trunk and aorta, with many elastic fibers.

Muscular Arteries

Medium-sized distribution arteries that go to specific organs, like the brachial and femoral arteries.

Resistance arteries

Small arteries with thick tunica media and very little tunica externa.

Arterioles

Smallest of the resistance arteries, controlling blood flow to various organs.

Capillaries

Smallest vessels with thin walls, part of the microvasculature, where exchange functions occur.

Continuous capillaries

Capillaries with complete endothelial lining, found in all tissues except certain areas.

Fenestrated capillaries

Capillaries with filtration pores allowing rapid exchange of water and small solutes.

Sinusoids

Capillaries with wide gaps between endothelial cells, allowing free exchange of large plasma proteins.

Precapillary Sphincter

Guards entrance to each capillary, opens and closes to regulate blood flow.

Veins

Capacitance vessels that are thin-walled, flaccid, and subject to low blood pressure.

Postcapillary venules

Smallest veins that are more porous than capillaries and exchange fluid with surrounding tissues.

Muscular venules

Receive blood from postcapillary venules and have one or two layers of smooth muscle.

Medium veins

Veins up to 10 mm in diameter with thin tunica media and thick tunica externa.

Large veins

Veins larger than 10 mm in diameter with smooth muscle in all three tunics.

Venous sinuses

Modified veins with thin walls, large lumens, and no smooth muscle.

Portal system

Blood flows through two consecutive capillary networks before returning to the heart.

Anastomosis

Convergence between two vessels other than capillaries.

Flow

Amount of blood flowing through an organ, tissue, or blood vessel at a given time (mL/min).

Perfusion

Flow per given volume or mass of tissue in a given time (mL/100g/min).

Blood pressure

Force blood exerts against a vessel wall, measured at the brachial artery.

Systolic pressure

Peak arterial BP taken during ventricular contraction.

Diastolic pressure

Minimum arterial BP taken during ventricular relaxation.

Pulse pressure

Difference between systolic and diastolic pressure.

Mean arterial pressure (MAP)

Diastolic pressure plus one-third of pulse pressure.

Peripheral resistance

Opposition to flow that blood encounters in vessels away from the heart.

Angiotensin II

Potent vasoconstrictor that raises blood pressure.

Aldosterone

Hormone that promotes sodium retention and increases blood volume and pressure.

Natriuretic peptides

Hormones secreted by the heart that increase sodium excretion.

Antidiuretic hormone (ADH)

Promotes water retention and raises blood pressure.

Diffusion

Movement of materials across capillary walls down concentration gradients.

Filtration

Driven by hydrostatic pressure, forcing water and small solutes through capillary walls.

Reabsorption

Process of drawing fluids back into the capillaries from the interstitial fluid.

Total blood flow to the brain

Fluctuates less than that of any other organ, approximately 700 mL/min.

Pulmonary circuit

Includes the pulmonary trunk, pulmonary arteries, and veins, facilitating gas exchange.

Tunica intima

Innermost layer of blood vessel walls, composed of endothelium, which repels blood cells and platelets.

Tunica adventitia

Outermost layer of blood vessel walls, made of loose connective tissue that anchors vessels to surrounding structures.

Blood flow to the brain

Fluctuates less than that of any other organ, with total flow at 700 mL/min.

Aorta

Major artery that branches off to supply blood to the body.

Mean arterial pressure (M A P)

Diastolic pressure plus one-third of pulse pressure.

Descending aorta

Passes downward

Thoracic aorta

Called the thoracic aorta above diaphragm

Abdominal aorta

Called the abdominal aorta below diaphragm

Common carotid arteries

Right and left common carotid arteries branch off the brachiocephalic trunk and aorta, respectively

External carotid artery

Gives rise to vessels that supply the neck and face

Internal carotid artery

Supplies the orbits and 80% of cerebrum

Dural venous sinuses

Blood-filled spaces between layers of dura mater that serve as large, thin-walled, modified veins

Internal jugular

Vein of the head and neck

External jugular

Vein of the head and neck

Internal thoracic artery

Branches from subclavian and is often used in bypass

Subclavian vein

Prominent vein carrying blood from shoulder region to heart

Brachial artery

Passes along humerus, branching just distal to elbow

Radial artery

Where pulse is taken

Ulnar artery

Vessel of the upper limb

Femoral vein

Sometimes used in bypass

Ascites

Abnormal abdominal distention due to accumulation of serous fluid in peritoneal cavity

Splenomegaly

Spleen enlarges and 'weeps' serous fluid

Transient ischemic attacks (TIA)

Brief episodes of cerebral ischemia caused by spasms of diseased cerebral arteries

Edema

Accumulation of excess fluid in a tissue

Hypovolemic shock

Loss of blood volume due to hemorrhage, diarrhea, vomiting, burns

Vascular shock

Normal blood volume with extreme vessel dilation

Coarctation

Narrowing of the aorta

Marfan's syndrome

A genetic defect of connective tissue that can lead to aortic aneurysm

Phlebitis

Inflammation of veins

Hematoma

Mass of blood; bruise

Hemangioma

Noncancerous tumors of tangled blood vessels and fibrous tissue

Petechiae

Pinpoint hemorrhages in the skin

Varicose veins

Bulging veins due to incompetent valves

Hemorrhoids

Varicose veins in the anal area

Orthostatic hypotension

Temporary low blood pressure and dizziness when rising

Atherosclerosis

Hardening of vessels due to plaque buildup

Aneurysm

Balloon-like bulge in an artery

Cardiac catheterization

Procedure to diagnose and treat cardiovascular conditions

CABG

Coronary Artery Bypass Graft, a type of bypass surgery

Metabolism of cardiac muscle

Cardiac muscle depends almost exclusively on aerobic respiration to make ATP.

Myoglobin and glycogen in cardiac muscle

Rich in myoglobin and glycogen.

Mitochondria in cardiac muscle

Huge mitochondria fill 25% of cell.

Fatigue resistance of cardiac muscle

Fatigue resistant because it makes little use of anaerobic fermentation or oxygen debt mechanisms.

Adaptability of cardiac muscle

Cardiac muscle is adaptable to different organic fuels.

Organic fuels used by cardiac muscle

Fatty acids (60%); glucose (35%); ketones, lactate, and amino acids (5%).

Vulnerability of cardiac muscle

More vulnerable to oxygen deficiency than lack of a specific fuel.

Location of the heart

Mediastinum, middle of the thoracic cavity where the heart is located.

Pericardium

Membrane surrounding heart.

Fibrous pericardium

Outer layer of the pericardium.

Serous pericardium

Inner layer of the pericardium.

Parietal layer of serous pericardium

Lines fibrous pericardium.

Visceral layer of serous pericardium

Adheres to heart surface and is outermost layer of heart itself.

Pericardial cavity

Space between parietal and visceral layers of serous pericardium, filled with 5 to 30 mL of pericardial fluid.

Heart wall layers

Three layers: epicardium, myocardium, and endocardium.

Epicardium

Visceral layer of serous pericardium; serous membrane covering heart.

Endocardium

Smooth inner lining of heart and blood vessels.

Myocardium

Layer of cardiac muscle; thickness is proportional to workload.

Fibrous skeleton

Collagenous and elastic fibers providing structural support and electrical insulation.

Atria

Most superior part of the heart, separated by interatrial septum.

Auricles

Flaps that allow for extra volume of blood.

Ventricles

Inferior to the atria, separated by interventricular septum.

Trabeculae carneae

Internal muscular ridges found in both ventricles.