Unit 2b: The Cardiovascular System

What words do you associate with … Cardio Vascular Cardiac Veins Heart Vascularisation of the endometrium Activity Vessels Exercise / work out

B – The Cardiovascular System Key areas: The structure and function of arteries, capillaries and veins The structure and function of the heart Pathology of cardio vascular disease (CVD) Blood glucose levels and obesity

KA 1: The structure and function of arteries, capillaries and veins Subtopics: Structure and function of blood vessels Exchange of materials between tissue fluid and cells This used to be in a spider diagram format!

KA1: Learning Outcomes Describe the blood flow around the body (in general basic terms) Describe the structure of arteries and veins using the following terms: Endothelium Central lumen Connective tissue Elastic fibres Smooth muscle Valves State the role of arteries, veins and capillaries State the function of valves Describe what happens to blood pressure as blood moves away from the heart State what is meant by vasoconstriction and describe how it is caused State what is meant by vasodilation and describe how it is caused

Blood flow around the body (basic) You need to the order in which blood flows through the vessels: Capillaries Artery Veins Artery Veins Capillaries

Blood flow around the body (basic) Blood circulates from the heart through the arteries to the capillaries to the veins and back to the heart. HEART arteries VEINS capillaries capillaries veins arteries HEART

Re-cap: what do you already know about the blood vessels Arteries Veins Capillaries FUNCTION Description of wall Valves present? Pulse present? EACH GROUP COULD HAVE 3 SHOW ME BAORDS (ONE FOR EACH VESSEL) AND TRY TO WORK TOGETHER TO COMPLETE THE TABLE TASK: use your show me boards to complete the table

Arteries carry blood away from the heart. The ARTERY Arteries carry blood away from the heart. The endothelium lining of the central lumen. This lining is then surrounded by layers of tissue. Outer layer: Connective tissue containing elastic fibres Middle layer: Contains smooth muscle with more elastic fibres The endothelium lining the central lumen of blood vessels is surrounded by layers of tissue. Central lumen The elastic walls of the arteries stretch and recoil to accommodate the surge of blood after each contraction of the heart.

The VEIN Veins carry blood towards the heart. The endothelium lining of the central lumen. Outer layer: Connective tissue containing elastic fibres Middle layer: Contains a much thinner muscular wall than arteries (also has elastic fibres) Central lumen (much wider than the artery lumen) Veins also contain VALVES. Valves prevent the BACKFLOW of blood A LOT more on valves in the next Key Area!!

VIDEO CLIP: Valves in action

TASK: Demonstrating the emptying of part of a vein in the arm

CAPPILARIES RED BLOOD CELLS THIN CELL WALL BODY CELLS

Arteries, Veins and Capillaries Capillaries have a wall which is ONE CELL THICK. This allows for the exchange of substances such as glucose and oxygen with the body tissues. Arteries carry high pressure blood away from the heart. Veins carry low pressure blood back to the heart.

Summary

Vasodilation

VIDEO CLIP: vasodilation vasoconstriction

Vasodilation Vasoconstriction This is the widening of blood vessels Caused by smooth muscle cells relaxing This results in the lumen becoming wider and blood flow increasing (To parts of the body such as skeletal muscles during exercise) This is the narrowing of blood vessels Caused by smooth muscle cells contracting This results in the lumen becoming narrower and blood flow decreasing (To parts of the body such as the small intestine during exercise)

KA1: Learning Outcomes Describe the blood flow around the body (in general basic terms) Describe the structure of arteries and veins using the following terms: Endothelium Central lumen Connective tissue Elastic fibres Smooth muscle Valves State the role of arteries, veins and capillaries State the function of valves Describe what happens to blood pressure as blood moves away from the heart State what is meant by vasoconstriction and describe how it is caused State what is meant by vasodilation and describe how it is caused