Unit J - Circulation and Blood .

Overview 1. 5 types of blood vessels 2. ID major blood vessels 3. Pulmonary vs. Systemic Circulation 4. Fetal circulation 5. Lymphatic System

Intro… When you are unicellular there is no need for a transport system… However when you are trillions of cells a system to transport nutrients (glucose, amino acids) and remove wastes (carbon dioxide, ammonia) is required….

Circulatory System Blood = the medium of transport (will carry nutrients & wastes) Blood vessels = pathway for blood Heart = pump that will move blood through vessels

5 type of blood vessels Arteries – arterioles (smaller version) Veins – venules (smaller version) Capillaries – smallest!!!

Arteries (10% of blood) Carry blood AWAY from heart Thick walls to withstand blood pressure Elastic muscle fibers to withstand blood pressure Highest blood Pressure Smooth muscle can regulate size

Arterioles Connects to arteries and capillaries Smaller than arteries Can dilate or constrict which regulates blood pressure

Veins (70% of blood) Carry blood Back to heart Thinner walls Contain Valves to prevent back flow Lowest blood pressure

Venules Connect veins to capillaries Very thin walls

Capillaries (20% of blood) Narrow, microscopic tubes, blood cells will pass through single file! Site of nutrient / waste exchange Thin walls allow for diffusion Large surface area allows for greater exchange of gases and nutrients Largest cross sectional area

The blood flow across the capillary bed is regulated by a sphincter muscle on the arteriole side.

Over 99 percent of the blood vessels in the body are capillaries,even though they only hold 20 percent of the body’s blood.

Capillary Bed

Blood vessels - compared

Capillary Bed

Capillary Fluid Exchange

Capillary Fluid Exchange 1. Arteriole Side - blood pressure (40 mm Hg) is higher than the osmotic pressure (25 mm Hg.). Fluid with oxygen & nutrients exit out of the blood (the walls of the capillaries) into the surrounding tissues. Blood proteins and blood cells are too big and remain in the capillaries.

Capillary Fluid Exchange 2. Middle - Oxygen, glucose and amino acids in the fluid diffuse into the cells. (PASSIVE TRANSPORT) CO2 and ammonia produced in the tissue cells diffuse out of the tissues. (PASSIVE TRANSPORT)

Capillary Fluid Exchange 3. Venule Side- blood pressure is now reduced (10 mm Hg.), and is less than osmotic pressure (25mm Hg.). Fluid (containing wastes) is now is moved by osmotic pressure back into the blood vessels. (PASSIVE TRANSPORT)

Capillary Fluid Exchange The remaining fluid enters lymph vessels carried back to the circulatory system…

Pulmonary vs. Systemic Pulmonary = Lungs Systemic = Body 2 circuits with 2 functions Pulmonary – from heart to lungs and back to heart…. Function ??? Return deoxygenated blood to capillaries in lungs (CO2 diffuses out, O2 diffuses in) Return oxygen rich blood to heart (the pump for oxygenated blood)

Systemic Systemic – from heart to EVERY cell of body and back to heart ….. Function???? Oxygenated blood delivered to cells (O2 diffuses out of blood, CO2 diffuses into blood) Deoxygenated blood return to heart (heart is the pump for blood)

Fetal Circulation Different - Why???

Fetal Circulation The fetus does not use pulmonary circuit Why???

Fetal Circulation Placenta - organ responsible for delivery of nutrients, removal of waste products and delivery of oxygenated blood to the fetus via diffusion and active transport mechanisms. 

Fetal Circulation – 4 differences AKA: The Fetal Four Umbilical cord Umbilical vein (1)- A vessel which delivers oxygenated and nutrient rich blood from the placenta to the fetus. Umbilical arteries (2) vessels that carries deoxygenated blood from iliac arteries out to the placenta. 2. Venous duct - receives blood from the umbilical vein and directs it to the posterior/inferior vena cava. This venous duct acts as a liver bypass and moves blood into the fetal systemic circulation. Function – to bypass the liver Why bypass the liver??

Fetal Circulation 3. Foramen Ovale - an opening between the right atrium and left atrium of the heart Function – to bypass the lungs Why bypass the lungs??

Fetal Circulation Ductus Arteriosus - A vessel that connects the pulmonary artery to the aorta. Function – to bypass pulmonary circuit.

Lymph System Is a one way transport system (tissues to blood) Takes excess fluid from capillary beds of body and returns it to the blood CONSISTS of lymph veins (have valves) and capillaries Fluid is called lymph Joins blood at subclavian vein

Main Functions of Lymphatic System Take up excess tissue fluid Transport fatty acids (from LACTEAL) Fight infection (lymphocytes) lymph system

Parts of Lymphatic System 1. LACTEAL: dead ends of lymph vessels in villi of the small intestine. 2. LYMPH NODES - small oval structures that produce and store lymphocytes, filter the lymph of damaged cells and debris. SPLEEN: stores blood. THYMUS GLAND -production and maturation of some lymphocytes.

PATH OF A BLOOD CELL THROUGH THE BODY Start in the Left Ventricle and go through the Circulatory System