Cardiovascular System Flashcards
4 Functions of the Cardiovascular System
- Nutrient and Waste Transport: blood transports absorbed nutrients to liver for processing, cells release waste products of metabolism into bloodstream
- O2 and CO2 Transport: cells need O2 for cellular respiration, O2 molecules diffuse into blood through walls of lungs
- Temperature Maintenance
- Hormone Circulation
Which side of the heart does (oxygenated) blood enter?
The left side
Which side of the heart does (deoxygenated) blood return to?
The right side
Which side of the heart has thicker muscle and why?
The left side of the heart has thicker muscle as it has to pump the blood to all the cells of the body. The right side of the heart only has to pump blood the short distance to the lungs.
How does the cardiovascular system function to maintain temperature?
- Blood distributes heat, helping to maintain a steady body temperature.
- Blood passes through networks of vessels that lie under the skin.
- Blood passing through these vessels releases heat and has a cooling effect.
What does the hypothalamus do? (2)
- Monitors body temperature
- Stimulates regulatory processes to constrict or dilate blood vessels
Cycle of Homeostasis:
Increased body temperature
- Stimulus: increased body temp, exercising/warm climate
- Blood warmer than hypothalamic set point
- Activates heat loss center in hypothalamus
- Sweat glands activated. They secrete perspiration which is vaporised by body heat, helping to cool the body.
- Skin blood vessels dilate, capillaries flush with warm blood, heat radiates from skin surface
- Body temp decreases, blood temp decreases, heat loss center in hypothalamus shuts off
- Homeostasis reached
Cycle of Homeostasis:
Decreased body temperature
- Stimulus: decreased body temp, cold climate
- Blood cooler than hypothalamic set point
- Activates heat promoting center in hypothalamus
- Skin blood vessels constrict, blood diverted from skin capillaries and withdrawn to deeper tissues. This minimises overall heat loss from skin surface
- Skeletal muscles activated when more heat must be generated: shivering
- Body temp increases, blood temp rises, hypothalamus heat promoting center shuts off
- Homeostasis reached
Definition of hormones
Chemical messengers that are produced in one place in the body and affect cells or tissues in another
How does the circulatory system aid in hormone circulation
The circulatory system is the travel vessel within which hormones travel throughout the body, from their site of production to the target tissues.
What is the pericardium
Double walled protective sac
The two layers of the pericardium
- Parietal pericardium: superficial part
- Visceral pericardium: inner pericardium
What is between the parietal pericardium and the visceral pericardium?
The pericardial fluid
What does the pericardium protect the heart from (3)
- Physical knocks
- Shocks
- Infection
The three layers of the heart wall
- Outer layer = epicardium or visceral pericardium
- Middle layer = myocardium (muscle)
- Inner layer = endocardium (in contact w the blood)
What is the bicuspid valve also known as
Mitral valve
Where are the bicuspid valve and tricuspid valve located
Between the atria and ventricles
Where are the two semilunar valves located
In the arteries leaving the heart
Describe how the blood vessels transport the blood
- Arteries carry blood away from the heart
- Into a network of capillaries
- The blood is forced through the capillaries, where gases, nutrients and metabolic wastes are exchanged between the blood and tissues
- Blood passes from the capillaries into venules
- A network of venules and larger veins collects the blood and brings it back to the heart
Why are capillaries one cell thick
To allow molecules to diffuse freely
Describe the aorta
The largest artery. It is the main vessel that carries blood from the heart to the body.
The 3 layers of tissue that make up the artery walls
- Tunica interna
- Tunica media
- Tunica externa
Describe the tunica interna
Endothelial cells in contact with the blood
Describe the tunica media
Thick layer of elastic fibres and smooth muscle
Describe the tunica externa
Layer of protective connective tissue