Anatomy & physiology 12 - Circulation

Even though this sucks, it's still better than chem 12

Arteries & Arterioles

• Carry blood away from heart

Arterioles

• Smaller branches of arteries

Inner Endothelium

• Provides a smooth surface (less friction)

• Contains elastic fibres

• Part of both veins & arteries

Thick Smooth Muscle Walls (arteries)

Thin smooth muscle walls (veins)

• Resist & control blood pressure

Collagen Layer

• Connective tissue

• Contains elastic fibres

• Part of both veins & arteries

Veins & Venules

• Carries blood towards the heart

Venules

• smaller branches that join to form a Vein

• drain blood from capillaries

Valves

• Can close to prevent backflow

• As part of veins/venules

Capillaries

• Vessels that are one cell layer thick, branching out from arterioles

• Gases (O₂ & CO₂) and small molecules (Glucose, Amino Acids) are able to be exchanged across cell membranes

• Sphincters & Smooth Muscles encircle the entrance

Capillary Beds

• Network of capillaries (at organs & muscles)

• The sphincters control blood flows to specific areas

  • e.g. more blood to muscles during exercise

  • e.g. more blood to stomach during digestion

Carotid Arteries & Jugular Veins

Blood to/from Head

Superior & Inferior Vena Cava

Blood from Body to Heart

Renal Artery & Vein

Blood to/from Kidney

Femoral/Iliac Artery & Femoral/Iliac Vein

Blood to/from Pelvis/Thighs

Subclavian Artery & Vein

Blood to/from Arms

Aorta

Blood from Heart to Body

Mesenteric Artery & Vein

Blood to/from Abdomen

Hepatic Vein

Processed blood from Liver to Heart

Hepatic Portal Vein

Blood from Intestines to Liver for processing

Superior Mesenteric Vein

Blood from Small Intestine to Hepatic Portal Vein

Inferior Mesenteric Vein

Blood from Colon to Hepatic Portal Vein

Arterial Duct (ductus arteriosus) - Fetal Circulation

• Connects pulmonary artery/aorta

• Blood that would have been pumped to Lungs is directed to Aorta instead

Oval Opening (foramen ovale) - Fetal Circulation

• Opening between right & left atrium of the heart, covered by flap (valve)

• Some blood bypasses the pulmonary circuit by directly moving between atria

• Normally, this closes after birth, if not, open heart surgery is required

Placenta - Fetal Circulation

• Vascularized membrane shared by mother & fetus

• Site of gas, nutrient & waste exchange (alcohol? drugs?)

Umbilical Arteries/Veins - Fetal Circulation

• Take deoxygenated blood to Placenta, receive oxygenated blood from it

Venous Duct (ductus venosus) - Fetal Circulation

• Attaches at fetus’s liver, bypass most of liver

• Connect Umbilical Vein to Vena Cava to bring blood back to fetus’s heart