Unit K – Heart Structure and Function Heart Quiz Unit K – Heart Structure and Function

Unit K – Heart Structure and Function First baby step – anatomy of heart heart review

Diagram (quiz…) Diagram (quiz…)

Parts of the Heart Left and Right Atria – Collecting Chambers -- Right: Collects blood from Venae Cavae -- Left: Collects blood from Pulmonary Veins Left and Right Ventricles – Pumps -- Right: Sends blood to the lungs via the Pulmonary Trunk. -- Left: Sends blood to the body via the Aorta

Atrioventricular-- Valves -- Valves between the atria and ventricles -- Prevent backflow of blood -- Right hand side “Tricuspids”— three cusps, or flaps (also known as right atrioventricular valve -- Left hand side “bicuspid”– two cusps (also known as the mitral valve or left atrioventricular valve)  Chordae Tendineae –Strong, Fibrous strings that support the A.V. valves --Keeps the valves from inverting with the force of blood flow.

Semi-Lunar Valves (no chordae tendineae) -- Between the ventricles and the Aorta (aortic valve) -- Between the ventricles and the Pulmonary Trunk (pulmonary valve)  

 Pulmonary Trunk -- Branches off to form the Pulmonary Artery -- Receives blood from the right ventricles   Septum -- The wall of the Heart -- Separates the left and right sides of the Heart

heart beat!

Control of Heart Heart is muscle tissue Beat of heart is INTRINSIC will beat independently of any nervous stimulation

Coordination of Heartbeat 2 nodes – SA node and AV node both located in the right atrium 1) SA node – sinoatrial node/ pacemaker – upper wall of right atrium. Acts as a pacemaker Activates muscle cells of both atria to contract almost simultaneously

Coordination of Heartbeat

Coordination of Heartbeat 2) AV node – atrioventricular node – base of r.a. impulse from SA node travels via nerves called the bundle of HIS AV node initiates contraction of both ventricles via Purkinje fibers

Coordination of Heartbeat SA node connected to brain via the Vagus nerve – brain signals SA node through this nerve and sets heart rate Medulla oblongata part of brain that monitors blood pressure Regulation is autonomic (not under conscious control)

Electrocardiogram ekg- a way to measure electrical activity of heart Measures the electrical activity of heart in millivolts (mV) This forms a graph that is then labeled PQRST P curve – atria contracting QRS – contraction of the ventricles T recovery Heart beat approx. 50 -80 beats/min.

ECG/EKG

The red line is the EKG. The blue line is aortic pressure The red line is the EKG. The blue line is aortic pressure. The green line shows heart sounds.

Blood Pressure Is the force of blood against the blood vessels Not constant & is greater when ventricles contract 2 parts – systolic pressure (systole) – pressure when ventricles contract – higher number – given first

Blood Pressure Diastolic pressure – diastole – pressure when ventricles are not contracting – atrial contraction Blood pressure is measured along a brachial artery 120/80 = normal Hypertension – high blood pressure (diet, stress, exercise)

Blood Pressure – cont’d Hypotension – low blood pressure Hypothalamus –part of brain that monitors blood pressure and can cause the arteries to constrict or dilate heart attack!