Cardiovascular systems

Artery 

Thick-walled vessel; carries blood away from heart. 

Location: Deep, round lumen, thick tunica media

Vein

Thin-walled vessel; carries blood to heart

Location: Superficial/deep; large irregular lumen

Tunica Intima

Inner layer: endothelium + CT

Location: Lines artery/vein lumen

Tunica Media

Smooth muscle + elastin; thick in arteries

Location: Middle layer

Tunica Externa

Fibrous CT; protects & anchors

Location:Outer layer

Arteriole

Small artery; major regulator of blood pressure

Location:Between arteries & capillaries

Venule

Small vein collecting from capillaries

Location: Between capillaries & veins

Capillary

Site of gas/nutrient exchange

Location: Everywhere—especially epithelia & organs

Lumen

Interior opening of vessel

Location: Center of all vessels

Endothelium

Simple squamous epithelium lining vessels

Location: Tunica intima

Erythrocytes (RBCs)

Transport O₂ and CO₂

Location: Within vessel lumen

Leukocytes (WBCs)

Immune response

Location: Circulating blood & CT

Vasa Vasorum

“Vessels of vessels”—feed large arteries

Location: Tunica externa of large arteries

Apex

Pointed tip of heart

Location: Left ventricle, caudal/ventral end

Base

Broad superior portion

Location: Where vessels connect, cranial/dorsal

Right & Left Atria

Receive blood (R = systemic; L = lungs)

Location: Upper chambers

Auricles

Flaplike extensions of atria

Location: On outer atrial surface

Pectinate muscle

Ridged muscle in atria

Location: Inside atria, especially right atrium

Interatrial Septum

Wall separating atria

Location:Midline between atria

Right & Left Ventricles

Pump blood (R → lungs; L → body)

Location: Lower chambers

Interventricular septum

Thick muscular wall between ventricles

Location: Midline between ventricles

R&L AV Valves

Tricuspid & mitral; prevent backflow to atria

Location: Between atria and ventricles

Semilunar Valves

Pulmonary & aortic valves; prevent backflow to ventricles

Location: Base of pulmonary trunk & aorta

Chordae Tendineae

Prevent valve prolapse

Location: Connect AV valves → papillary muscles

Papillary Muscles

Contract to stabilize AV valves

Location: Ventricular walls

Trabeculae Carneae

Irregular muscular ridges

Location: Inside ventricles

Fossa Ovalis (foramen ovale)

Fetal shunt atrium-to-atrium; closes after birth

Location: Interatrial septum

Ligamentum Arteriosum (ductus arteriosus)

Fetal shunt pulmonary trunk → aorta

Location: Between aorta & pulmonary trunk

Aorta

Main systemic artery

Location: Leaves left ventricle

Vena Cava (cranial/caudal)

Returns deoxygenated blood

Location: Enters right atrium

Pulmonary trunk

Sends blood to lungs

Location: From right ventricle

Pulmonary arteries

Carry deoxygenated blood to lungs

Location: Branch off pulmonary trunk

Pulmonary veins

Carry oxygenated blood to left atrium

Location: From lungs → left atrium

Coronary Arteries & Veins

Supply heart muscle

Location: Surface of heart

Brachiocephalic A/V

Supply/drain upper body

Location: Off aortic arch / into vena cava

Carotid Arteries

Supply head and brain

Location: Neck region

Cerebral Circle

Arterial circle supplying the brain

Location: Base of Brain

Brachial A/V

Supply/drain arms

Location: Upper limbs

Femoral A/V

Supply/drain legs

Location: Thigh region

Celiac Artery

Supplies stomach, liver, spleen

Location:Abdominal cavity

Mesenteric A/V

Supply intestines

Location: Intestinal mesentery

Hepatic Portal Vein

Gut → liver for filtration

Location: liver hilum

Renal A/v

Supply/drain kidneys

Location: Kidney hilum

Gonadal A/V

Supply testes/ovaries

Location: Abdominopelvic cavity