Human Body: Cardiovascular System

Closed vs. Open Circulatory System

Transport in the Vertebrates All vertebrates have a closed cardiovascular system 2 parts: 1.Vertebrate heart –Atrial chamber(s) of heart receive blood from general circulation –Ventricle chamber(s) of heart pump blood out through blood vessels

Transport in the Vertebrates All vertebrates have a closed cardiovascular system 2 parts 1.Vertebrate heart 2.Vertebrate vessels –Arteries - Carry blood away from heart –Veins - Return blood to heart –Capillaries - Exchange materials with tissue fluid –Arterioles - Lead to capillaries –Venules - Lead to veins

Vertebrate Circulation

Birds and Mammals

Human Circulation Human Heart –Fist-sized –Cone-shaped –Very muscular organ (special cardiac fibers) –Lies within a fluid-filled sac (the pericardium)

Human Heart Septum separates heart into left & right halves Each half has two chambers –Atria - upper Thin-walled Receive blood from circulation –Ventricles - lower Thick-walled Pump blood away from heart

External Heart Anatomy

Internal View of the Heart

Human Heart: Valves Valves open and close to control blood flow through heart –Atrioventricular valves Tricuspid Bicuspid –Semilunar valves Pulmonary Aortic

Transport in Humans

Heartbeat

P wave is the electrical signature that causes atrial contraction Atria contract simultaneously. QRS is the electrical signature of the ventricles contraction Q wave - small horizontal (left to right) current R and S waves indicate contraction of the myocardium itself. T wave represents the repolarization of the ventricles. Why do they need to repolarize??

Heartbeat

Vascular Pathways Human cardiovascular system includes two major circular pathways: 1. Pulmonary Circuit Takes oxygen-poor blood to the lungs and returns oxygen-rich blood to the heart

Vascular Pathways Human cardiovascular system includes two major circular pathways: 1. Pulmonary Circuit 2. Systemic Circuit Takes blood throughout the body from the aorta to the vena cava

Velocity and Blood Pressure

Cross Section of Valve in a Vein

Blood Pressure The beat of the heart = pressure that keeps blood moving in the arteries Skeletal muscle contraction pushes blood in the veins toward the heart

Blood Pressure Blood pressure –Normally measured on the brachial artery –Expressed in the form: Systolic “over” Diastolic Systolic Pressure - blood forced into the arteries during ventricular contraction Diastolic Pressure is the pressure in the arteries between contractions

Cardiovascular Disorders Hypertension - High blood pressure

Cardiovascular Disorders Stroke - Cranial arteriole bursts or is blocked by an embolus

Cardiovascular Disorders Heart attack – Coronary artery becomes partially blocked

Cardiovascular Disorders Angina pectoris – Painful squeezing sensation from myocardial oxygen insufficiency

Blood Functions 1. Transports substances to and from capillaries for exchange with tissue fluid 2. Guards against pathogen invasion 3. Regulates body temperature 4. Buffers body pH 5. Maintain osmotic pressure 6. Clots prevent blood/fluid loss

Red Blood Cells Contain the protein hemoglobin Carries Oxygen around the body** Hemoglobin contains –Iron-containing heme –Made in bone marrow

White Blood Cells Refers to a blood cell without hemoglobin. Made by the bone marrow Help fight infection and other diseases, as part of the immune system. –Phagocytize foreign material –Lymphocytes (T Cells) attack infected cells –Antigens cause body to produce antibodies

Platelets –Involved in coagulation Blood clot consists of –Platelets –Red blood cells –All entangled within fibrin threads

Capillary Exchange Capillaries very narrow – Tiny RBCs must go through single file Wall of capillaries very thin to facilitate diffusion of nutrients, gasses and wastes

Capillary Exchange Oxygen and nutrients exit a capillary near the arterial end Carbon dioxide and waste molecules enter a capillary near the venous end

Capillary Bed

Human Body: Respiratory System

Gas Exchange Respiration –The events associated with gas exchange between the cells and the external environment

Gas Exchange Surfaces Needs for effective, gas-exchange: –Regions must be Moist Thin Relatively large (  Surface Area/Vol - vascularization) Delivery to cells is promoted by respiratory pigments (like hemoglobin)

Ventilation At rest the ribs are collapsed and hanging down. The diaphragm muscles are relaxed resulting in the diaphragm being dome shaped.

Ventilation in Terrestrial Vertebrates Inhale Create negative pressure in lungs – The rib cage is elevated – The diaphragm lowers – Atmospheric pressure forces air into the lungs

Human Respiratory System As air moves through upper respiratory system –It is filtered to free it of debris –Warmed, and –Humidified When air reaches lungs –It is at body temperature, and –Its humidity is 100%

Upper Respiratory System Air flow: Pharynx  Glottis  Larynx  Trachea  Lung

Upper Respiratory System When food is swallowed –The larynx rises, and –The glottis is closed by the epiglottis –Backward movement of soft palate covers the nasal passages into the pharynx

Lower Respiratory System Trachea divides –Forms two primary bronchi (to the right and left lungs) Bronchi branch into a number of tiny bronchioles –Each bronchiole terminates in an elongated space enclosed by alveoli

Gas Exchange and Transport Breathing is stimulated by increased CO 2 concentrations in the blood Oxygen diffuses into pulmonary capillaries –Most combines with hemoglobin in red blood cells CO 2 diffuses out of pulmonary capillaries –With hemoglobin and as a bicarbonate ion

Hemoglobin - Protein (4°)

Common Bronchial and Pulmonary Diseases

Respiration and Health Upper Respiratory Tract Infections –Strep Throat (Streptococcus pyogenes) –Sinusitis - sinuse infection –Tonsillitis - tonsil infection –Laryngitis - larynx infection

Respiration and Health Lower Respiratory Tract Infections –Acute bronchitis Infection of primary and secondary bronchi –Pneumonia Viral or bacterial infection of the lungs where bronchi and alveoli fill with fluid –Pulmonary tuberculosis Caused by tubercle bacillus

Disorders Chronic bronchitis –Airways inflamed and filled with mucus Emphysema –Alveoli burst and refuse -- this damage causes a decrease in surface area available for gas exchange

Disorders Asthma –Airways are unusually sensitive to specific irritants When exposed to the irritants, the smooth muscles in the bronchioles undergo spasms Lung Cancer –Begins with thickening and callusing of the cells lining the airways