Module 15: Vascular System Flashcards
What is the role of arteries?
Carry blood away from the heart
What is the role of veins?
Return blood to the heart
What is the role of capillaries?
Connect the smallest arteries to the smallest veins
What is the role of conducting arteries (elastic arteries)?
Give examples
Expand as blood surges into them and recoil when the ventricles relax.
Ex. Aorta, common carotid artery, subclavian artery
known as muscular arteries - These arteries carry blood father way from the heart to specific organs and areas of the body. Examples: brachial, femoral, and renal arteries
Distributing arteries
Known as resistant vessels - Through the contraction of smooth muscle in their walls, they can resist the flow of blood, thus helping regulate blood pressure as well as control how much blood enters an organ. What artery is this and how are they connected?
Arterioles - Connected to capillaries by short connecting vessels called metarterioles
Veins become _______________ as they lead back to the heart
Converge, forming progressively larger and fewer vessels
What are three structural functions of the veins?
- Have thinner walls than arteries
- Have a great ability to stretch
- Can constrict extensively
Why are capillaries called the exchange vessels?
It’s within capillaries that nutrients, waste, and hormones are transferred between blood and tissues
What is the structure of capillaries?
Have extremely thin walls and very small diameters
Why do you precapillary sphincters open during exercise?
Muscles demand an abundance of blood.
When skeletal muscles require more oxygen, the precapillary sphincters open, blood fills the capillary network, and exchange of oxygen, nutrients, and wastes occurs with the tissue fluid.
What happens to precapillary sphincters when the body is at rest?
They close. Blood bypasses the capillary bed and flows directly into a venule to begin its journey back to the heart and lungs
The walls of the capillary allow for?
Two-way exchange of substances and fluids
What do the mechanisms of exchange include?
Diffusion, filtration, and osmosis
What do capillaries release?
Chemicals, including oxygen, glucose, hormones, and nutrients that will be used by surrounding tissues
What do capillaries take up?
Waste such as carbon dioxide and ammonia.
Glucose, calcium, antibodies, and hormones - substances that need to be transported to other parts of the body.
What is diffusion?
Substances move from areas of greater to lesser concentration
What is the role of diffusion in capillary exchange?
Allows for the exchange of nutrients and waste products
On what end of the capillary bed does filtration occur?
Arterial side
What is the role of filtration in capillary exchange?
The higher pressure in the capillary pushes plasma and dissolved nutrients (such as glucose and amino acids) through the capillary wall and into the fluid in the surrounding tissues
The lower pressure allows proteins in the blood, such as albumin, to exert what’s known as
Colloid osmotic pressure
What is the role of albumin (protein) in colloid osmotic pressure?
Albumin in the blood pulls tissue fluid, along with the cells waste products, into the capillaries
What is the role of pulmonary circulation?
Routs blood to and from the lungs to exchange carbon dioxide for oxygen
What circulation system provides the lung tissue with oxygen?
Systemic circulation