cardiovascular system and immune system. the function of the circulatory system is… transport...
TRANSCRIPT
The function of the circulatory system is…
• Transport blood and materials in the blood (oxygen, food) around the body to the cells.
Path of blood
• Veins from the body right side of heart lungs left side of heart Arteries to the body
Capillaries:
• Smallest blood vessels.• Very thin to allow diffusion of
oxygen, food and waste• Next to or near most cells
Veins:
• Venuoles combine to form veins• Have large diameters• Have valves to prevent back flow
of blood. • Return blood to heart.
Heart:
• 1. Function: pump blood• 2. Size: about the size of your fist• 3. Composition: cardiac muscle• 4. Pericardium: protective
sack/membrane around the heart. Filled with fluid to reduce friction.
The heart has four chambers
• 1. Right atrium– Recieves blood from the body
• 2. Right ventricle– Pumps blood to the lungs
• 3. Left atrium– Receives oxygenated blood from the
lungs
• 4. Left ventricle– Pumps blood to the body
• The heart is divided by the septum
• The heart is a double pump…– The right side pumps to the LUNGS
– The left side pumps to the BODY
Valves: one way path
A-V valves = valves between the atrium and ventricles
Semi-lunar valves = valves between the ventricles and main arteries.
Heartbeat Cycle:
• Diastole: heart relaxes
• Systole: heart contracts
• Heart murmur: heart valves don’t close completely and blood leaks backwards. Makes a woosh sound.
Control of the heartbeat:
• Cardiac muscle: atria contract together then ventricles contract together
• S-A node: pace-maker of the heart. Sends out electrical signals that tell the heart how fast or slow to beat.
Control of heartbeat cont.
• A-V node: sends signal to ventricles to contract
• ECG: a machine that measures the electrical impulses of the heart
• Artificial pace-maker: if your S-A node is not working, an artificial pace-maker regulates your heart beat.
Blood Pressure:
• 1. Arteries: blood pressure is highest here.
• 2. Pulse: Arteries expanding with blood.
• 120/80 = normal blood pressure.
• 120 = when heart is contracting• 80 = when heart is relaxing
• What causes blood pressure to go up or down?
• Hypertension: chronic high blood pressure. Heart has to work harder.
• Arteriosclerosis: hardening of the arteries. Deposits of cholesterol.
• Vein blood pressure: lowest blood pressure. Need valves and muscle movement to move blood.
Circulation of blood• William Harvey: identified correct
pathway of blood circulation.
• Pulmonary Circulation = to lungs
• Systemic Circulation = to body– Coronary circulation = to heart– Hepatic circulation = to liver– Renal circulation = to kidneys
Blood is a fluid tissue
• Functions: Transportation
• Brings oxygen and food to cells• Removes CO2 and other wastes
from cells.• Brings hormones (chemical
messengers) to cells
Regulation: • Body temperature: heat escapes
from blood to the skin, then air.
• Blood pH is 7.4. Carbon dioxide must be removed to maintain stable pH.
• Water balance: fluids go in or out of blood depending on water needs.
• Red Blood Cells– Function: carry oxygen to cells– Structure: Bi-concave disc, no nucleus.
They live for 4 months.– Made in bone marrow
– Hemoglobin: a protein that carries oxygen.
• White blood cells:– Defenders of the body– Has a nucleus, larger than red blood
cells– Made in bone marrow– Can move around body on its own.
– Lymphocytes: Produce antibodies which fight foreign stuff.
• Normal white blood cell count: 7000 to 10,000 /mm3
• Elevated white blood cell count when sick: 30,000/ mm3
Circulation of Lymph
• 1. All cells of the body are bathed in a colorless, water fluid called intercellular fluid or interstitial fluid
• 2. This fluid helps to move materials between the capillaries and cells
• The excess fluid and proteins from the intercellular spaces are returned to the blood by a system of vessels called the lymphatic system.
Spleen
• A lymphatic tissue that stores blood and filters out bacteria and worn out red blood cells.
• First line defenses:– Skin, sweat, saliva, mucus
• Second-line defenses:– Inflammatory response: heat,
swelling , pain, pus. – Phagocytes = white blood cells that
eat bacteria and dead cells
• Third line defenses = Immune system
• Immunity = the body fights infections by making antibodies and white blood cells that inactivate foreign substances.
• Primary immune response:– The first time a pathogen enters the
body, the body makes antibodies and fights it off.
• Secondary Immune Response:– After the body has been exposed to a
disease the body has memory cells which will quickly recognize and fight the disease.
• Active immunity: Body produces its own antibodies to fight infections.
• Vaccinations: Dead or weakened pathogens which stimulate the immune system to produce antibodies to fight the disease.
• Passive Immunity: – Antibodies are obtained from another
person (from your mom when you are a baby or from an injection when you are older)
– Temporary immunity
Blood Typing
All cells, including blood cells have antigens on their surface.
There are two types of antigens on blood… A or B
The body makes antibodies to fight foreign antigens.
Blood Type Antigens Antibodies (in plasma)
A A Anti-B
B B Anti-A
AB A and B none
O None Anti-A and Anti-B
Blood type Can receive from…
Can donate to…
A A and O A and AB
B B and O B and AB
AB A, B, and O AB
O O A, B and AB