Physiology I

What are the adaptations of capillaries for material exchange?

Thin walls, large surface area, permeable, one layer of endothelium, and allows small/medium particles to pass.

What is the primary function of arteries?

Carry high-pressure blood away from the heart to the organs.

How do veins facilitate blood flow back to the heart?

They have thinner walls, contain valves to prevent backflow, and rely on muscle contractions and gravity.

What causes occlusion of coronary arteries?

Fatty deposits or plaque buildup, often due to risk factors such as hypertension, smoking, and obesity.

What is homeostasis?

The maintenance of a constant internal environment in the body.

What is the role of negative feedback loops in homeostasis?

To monitor and correct changes in a variable, restoring original levels.

How do insulin and glucagon regulate blood glucose levels?

Insulin lowers blood glucose by stimulating uptake in tissues, while glucagon raises it by converting glycogen to glucose.

What is the difference between Type I and Type II diabetes?

Type I is autoimmune (beta cells destroyed), while Type II is due to insulin resistance, often linked to lifestyle factors.

What are the physiological responses to heat during thermoregulation?

Vasodilation increases blood flow to the skin and sweating cools the body through evaporation.

What are the main components transported by blood?

Oxygen, carbon dioxide, nutrients, hormones, waste products, immune cells, and platelets.

What is the structure and function of capillaries?

Capillaries have thin walls and a narrow diameter to allow for gas and nutrient exchange between blood and tissues.

What adaptations do xylem vessels have for water transport?

Continuous tubes with thickened walls containing lignin, allowing them to withstand pressure.

How does the body respond to cold temperatures?

Vasoconstriction reduces blood flow to the skin, shivering generates heat, and hair erection traps air for insulation.

What is the significance of coronary arteries?

They supply oxygen and nutrients to the heart, which is vital for maintaining heart function.

What is thermoregulation?

The process that maintains body temperature within a certain range through various physiological responses.

What are the layers of an artery wall?

Tunica externa (collagen), tunica media (smooth muscle and elastin), tunica intima (endothelium).