Untitled Quiz

Blood Vessels

Blood vessels carry blood throughout the body. There are three main types: arteries, veins, and capillaries.
Arteries carry blood away from the heart, veins carry blood towards the heart.
Most arteries carry oxygenated blood, except for the pulmonary artery, which carries deoxygenated blood to the lungs.
Most veins carry deoxygenated blood, except for the four pulmonary veins, which carry oxygenated blood from the lungs to the heart.
Capillaries are tiny vessels that connect arteries to veins, allowing for gas and nutrient exchange.
Sinusoids are specialized capillaries found in specific organs like the liver, spleen, and bone marrow.
Arteriovenous anastomoses are direct connections between arteries and veins, bypassing capillaries in some areas.
Cavernous tissue is a type of tissue found in the penis, containing small spaces lined with endothelium.

Circulation of Blood

Circulation refers to the movement of blood throughout the body. There are three main types: pulmonary, systemic, and portal.
Pulmonary circulation involves the movement of blood from the heart's right ventricle through the pulmonary arteries to the lungs, where it picks up oxygen, and then back to the heart's left atrium through the pulmonary veins.
Systemic circulation involves the movement of oxygenated blood from the heart's left ventricle through the aorta to the body, where it delivers oxygen and nutrients, and then back to the heart's right atrium through the superior and inferior vena cava.
Portal circulation is a specialized type of circulation that involves the movement of blood from the digestive system to the liver. It has two steps:
- Blood from the intestines, pancreas, and spleen is collected into the portal vein.
- The portal vein branches into sinusoids within the liver, where the blood is filtered and processed before returning to the systemic circulation.

Main Arteries of the Body

The aorta is the largest artery in the body and arises from the left ventricle of the heart.
The aorta is divided into three parts: the ascending aorta, the arch of the aorta, and the descending aorta.
Ascending aorta: Gives rise to the right and left coronary arteries, which supply blood to the heart.
Arch of aorta: Gives rise to the brachiocephalic artery, the left common carotid artery, and the left subclavian artery.
- The brachiocephalic artery divides into the right common carotid artery and the right subclavian artery.
- The right and left common carotid arteries supply blood to the right and left sides of the head and neck, respectively.
- The right and left subclavian arteries supply blood to the right and left shoulders and arms, respectively.
Descending aorta:
- The descending aorta is further divided into the thoracic aorta and the abdominal aorta.
- The thoracic aorta supplies blood to the chest wall and spinal cord.
- The abdominal aorta supplies blood to the abdominal organs.
- The abdominal aorta gives rise to the coeliac, superior mesenteric, and inferior mesenteric arteries.
- The coeliac artery supplies blood to the stomach, liver, spleen, and pancreas. - The superior mesenteric artery supplies blood to the small intestine and part of the large intestine. - The inferior mesenteric artery supplies blood to the rest of the large intestine.
The descending aorta ends by dividing into the right and left common iliac arteries at the level of the fourth lumbar vertebra.
- The right and left common iliac arteries further divide to form the internal iliac arteries and the external iliac arteries.
- The internal iliac arteries supply blood to the pelvic organs, buttocks, and thighs.
- The external iliac arteries continue as the femoral arteries, which are the main arteries of the lower limbs.

Main Veins of the Body

Superior vena cava (SVC): Collects blood from the head, neck, upper limbs, and chest and returns it to the right atrium of the heart.
- Innominate or brachiocephalic veins: Are formed by the union of the internal jugular and subclavian veins on each side of the body. The right and left innominate veins converge to form the superior vena cava.
Inferior vena cava (IVC): Collects blood from the abdomen, pelvis, and lower limbs and returns it to the right atrium of the heart.
- Common iliac veins: Are formed by the union of the internal and external iliac veins on each side of the body. The right and left common iliac veins converge to form the inferior vena cava.
Other veins: Include the following:
- Internal Jugular veins: Collect blood from the head and neck.
- Subclavian veins: Collect blood from the shoulders and upper limbs.
- Axillary veins: Collect blood from the armpit area.
- Femoral veins: Collect blood from the thighs.
- External iliac veins: Collect blood from the pelvis and lower limbs.
- Internal iliac veins: Collect blood from the pelvic organs.

Pulmonary Circulation:

The passage of blood from the left ventricle into the right atrium is called pulmonary circulation.

Portal Circulation:

The circulation related to the liver is called portal circulation.

Artery carrying deoxygenated blood:

The pulmonary artery carries deoxygenated blood from the right ventricle of the heart to the lungs.

Branches of ascending aorta:

Branches of the ascending aorta include the right and left coronary arteries.

Branches of arch of aorta:

Branches of the arch of aorta include the brachiocephalic artery, the left common carotid artery, and the left subclavian artery.

What is portal circulation?

Portal circulation involves the movement of blood rich in nutrients and toxins collected from the digestive tract, pancreas, and spleen through the portal vein to the liver. Within the liver, the portal vein branches into sinusoids where blood is processed before returning to the systemic circulation via the hepatic veins, ultimately joining the inferior vena cava. This process plays a crucial role in detoxification and nutrient processing for the body.