lecture 14 ppt

July 23, 2018 | Author: Anonymous | Category: N/A
Share Embed

Short Description

Download lecture 14 ppt...



Thought Question: What are the functions of your circulatory system?


Lecture 14 Outline (Ch. 42) I.

Circulatory Systems


Human Heart

III. Blood IV. Blood Vessels V.

Cardiovascular disorders

VI. Lymph VII. Gas Exchange (Bulk Flow & Diffusion) VIII. Gas Transport IX. Breathing X.

Respiratory problems & Smoking

XI. Lecture Concepts


Circulation Overview Circulation carries energy, dissolved gasses, wastes

• •

Connects individual cells in distant parts of body Requirements – Blood – fluid for transport – Blood vessels – channels for transport – Heart – pump for circulation 4

Circulation Overview Circulatory systems are open or closed • •

Open- bathes organs in a hemocoel Closed- direct vessel connections to organs Heart

Hemolymph in sinuses surrounding organs



Blood Interstitial fluid

Small branch vessels In each organ

Dorsal vessel (main heart)

Tubular heart (a) An open circulatory system

Auxiliary hearts

Ventral vessels

(b) A closed circulatory system


Circulation Overview Vertebrates have a closed circulatory system •

More efficient – Blood is 5 – 10% of body volume – Blood flow is more rapid – Blood pressure is higher Multifunctional – Transport dissolved gasses – Distribute nutrients – Transport waste – Distribute hormones – Thermoregulation – Circulate immunodefenses


The Vertebrate Heart

Set of muscular chambers

Atria collect blood Ventricles send blood through body

The heart has evolved 7

Heart 4-chambered heart: A closer look

2 pumps

• •

Right: deoxygenated blood Left: oxygenated blood


Heart •

Right atrium receives deO2 blood from veins – Superior vena cava

– Inferior vena cava

Right ventricle pumps deO2 blood to lungs through pulmonary arteries Pumps into right ventricle 9

Heart •

Oxygenated blood returns to left atrium from lungs via pulmonary veins

Oxygenated blood pumped to body through aorta

Pumps into left ventricle 10

Heart Cardiac muscle contracts •

Present only in the heart

Cells linked by intercalated discs Prevents strong contractions from tearing muscle Allows rapid spread of electrical signal for simultaneous regional contraction


Heart The Cardiac Cycle •

Coordinated contractions of atria & ventricles


Heart The Cardiac Cycle & Blood Pressure •

Systolic – Ventricular contractions (higher pressure) Diastolic – Period between contractions (lower pressure)

Normal blood pressure ~120/80 13

Heart Keeping blood moving • •

Heart valves maintain oneway flow Atrioventricular valves – Between atria & ventricles Semilunar valves – Between ventricles & arteries


Heart Keeping blood moving • •

Pacemaker cells initiate and coordinate contractions Sinoatrial (SA) node – Primary pacemaker – Stimulates atrial contractions Atrioventricular (AV) node – Slows impulse received from SA node – Delays ventricular contraction until after atrial contractions have filled them with blood 15

Blood Plasma

• •

Primarily water Dissolved proteins and electrolytes


• •

Plasma fluid Cells – Red blood cells – transport – White blood cells – defense – Platelets – clotting


Blood Red blood cells: Erythrocytes • • •

Most abundant blood cells (over 99%) Transport O2 and CO2 Iron-based hemoglobin protein binds to O2 and transports from areas of high concentration to low concentration


Blood Erythrocytes are short-lived • • • •

Formed in bone marrow Lack nuclei (cannot divide or make proteins) Dead cells are removed by liver and spleen – Iron is recycled, although some is excreted Number of erythrocytes maintained by negative feedback


Blood White blood cells: leukocytes • •

Less than 1% of blood cells Disease defense – – – – –

Consume foreign particles (macrophages) Produce antibodies (lymphocytes)


Blood Platelets • •

Cellular fragments aid blood clotting Ruptured cells and platelets work together to produce substances that plug damaged vessels Scabs are platelets embedded in web of fibrin proteins


Blood is carried in vessels






100 µm Basal lamina

Endothelium Smooth muscle Connective tissue

Endothelium Smooth muscle Capillary

Connective tissue




15 µm

Red blood cell





Blood Vessels Arteries

Arterioles Arteries

• Carry blood away from heart • Thick-walled: Heart


• Smooth muscle/elastic fibers • Withstand high pressure


Venules 23

Blood Vessels Arteries

Arterioles Arterioles

• Control distribution of blood flow • Smooth muscle expands / contracts • Under hormone / NS control Capillaries Heart


Venules 24

Blood Vessels • • • •

Arterioles Contract walls: redirects blood to heart and muscles when needed (stress, exercise, cold) Relax walls: brings more blood to skin capillaries to dissipate excess heat Precapillary sphincters control blood flow to capillaries


Blood Vessels Arteries

Arterioles Capillaries

• Nutrients/waste exchanged with cells: • Vessel wall one-cell thick • Blood flow very slow Capillaries Heart

• Materials exit/enter via diffusion


Venules 26

Blood Vessels

Capillaries connect & exchange • •

Tiny vessels Connect arterioles and venules

Interstitial fluid leaks from plasma in capillaries and provides cells with means of exchange


Blood Vessels Arteries


Venules & Veins • Carry blood towards the heart Heart


• Thin-walled; large diameter • One-way to prevent backflow


Venules 28

Blood Vessels Skeletal Muscle Pump:

Vein Valve:


Blood Vessels Varicose veins occur if the vein valves become inefficient


Blood Vessels Cardiovascular Disorders: • Leading cause of death in the United States 1) Hypertension = High blood pressure •  Resistance in vessels =  work for heart 2) Atherosclerosis = Deposits (plaques) collect in vessels Connective tissue

Smooth muscle




(a) Normal artery

50 µm (b) Partly clogged artery

250 µm

Lymph The lymphatic system • • •

Coordinates with circulatory system Includes: lymph nodes, vessels, and glands – Tonsils contain large numbers of lymphocytes – Thymus matures white blood cells – Spleen filters blood 32

Lymph Elephantiasis Condition caused by parasitic worm infection of the lymphatic system.

Symptoms most common in legs and genitals


Lymph The lymphatic system •

Returns fluid to bloodstream –

• •

Lymph capillaries reabsorb interstitial fluid

Move fats to bloodstream from small intestine Bodily defense –

Contain masses of white blood cells in nodes


Lymph Lymphatic vessels •

Narrow, thinwalled

Cellular openings act as one-way valves

Dead-end in tissues, collect materials flow back to larger blood vessels 35

Thought Question: If you are an athlete who trains at high elevations, what happens if you compete at a lower elevation?



Living things process energy • They need oxygen for this - how do they get it?


Overview Cellular respiration uses O2 and produces CO2 •

C6H12O6 + O2  CO2 + H2O + ATP energy

Breathing – respiration supports this process by exchanging gasses


Gas Exchange Systems Exchanging gasses •

Moist surface –

• •

Gasses dissolve in water to move in/out of cells

Thin Large surface area


Gas Exchange Systems Who needs a respiratory system?

•I don’t! • • •

Moist environment Small (or thin) Low energy demand

•I do! • • •

Dryer environment Large or thick-bodied High energy demand


Gas Exchange Systems Respiratory systems enable gas exchange •

Bulk flow – Fluids move in bulk – Air/water move to respiratory surface – Blood moves through vessels Diffusion – Individual molecules move down concentration gradients – Gas exchange across respiratory surface – Gas exchange in tissues


Gas Exchange Systems Gills • •

Aquatic gas exchange Delicate folded membranes


Gas Exchange Systems Gills facilitate gas exchange in aquatic environments (e.g. fish):

• Elaborately folded ( surface area) • Contain capillary beds • Gill size inversely related to [O2] • Large gills = low [O2] 43

Gas Exchange Systems Fish Efficiency •

Dissolved O2 is < 1% of water (21% of air)

Countercurrent exchange increases efficiency


Gas Exchange Systems Terrestrial respiration •

Internal – Stay moist & supported

Insects have tracheae – Air enters/exits through spiracles – Branching channels (trachioles) allow gas exchange with cells 45

Gas Exchange Systems Vertebrate respiration •

Terrestrial use of lungs –

Evolved from accessory respiratory organs of freshwater fish

Amphibians are weird – – –

Remain tied to water Larval gills to adult lungs Moist skin transfers gasses


Gas Exchange Systems Reptiles & Mammals use lungs exclusively • •

Lack permeable skin Lungs are more efficient – Especially birds!


Mammals Human Respiration • • •

Air enters through nose and mouth to pharynx Travels through larynx (voice box) Epiglottis directs travel


Human Respiration On to the lungs • • • •

Trachea  Bronchi  Bronchioles  Alveoli


Human Respiration Air is warmed & cleaned • •

• • •

Dust & bacteria trapped by mucus Swept up and out by cilia

Microscopic chambers provide enormous surface area Surfactant keeps surface moist Association with capillaries – Diffusion of gasses 50

Lungs Diffusion •

Blood arrives from pulmonary artery

Low in O2 – Higher concentration in air diffuses into blood High in CO2 – Higher concentration in blood diffuses into air


Transport of gasses O2 Transport •

Binds to hemoglobin – Removes O2 from plasma solution – Increases concentration gradient; favors diffusion from air CO binds more tightly to hemoglobin than O2 Prevents O2 transport 52

Transport of gasses CO2 Transport • • •

Binds hemoglobin loosely Dissolved in plasma Combines with H20 to form bicarbonate (HCO3-) –

More CO2 = lower pH

The Bohr Effect: Hemoglobin binds more tightly to O2 when pH is increased and loosely when pH is decreased


Breathing Mechanisms The diaphragm helps move air in and out •

Inhalation – Chest cavity expands – Draws air in

Exhalation – Chest cavity shrinks – Forces air out


Breathing Mechanisms Breathing is involuntary • •

Controlled by the respiratory center of the brain Adjusts breath rate and volume based on sensory input – Maintain a constant concentration of CO2


Respiratory Problems Asthma • • • •

Smooth muscle in bronchioles is excitable and constricts or spasms Increased mucus production clogs passages Can lead to collapse Some genetic factors, linked to air quality


Respiratory Problems Emphysema • •

Alveoli rupture or become brittle Reduces surface area available for gas exchange

Labored and difficult breathing

Usually linked with smoking


Respiratory Problems Bronchitis & Pneumonia • •

Inflammations of respiratory passages & lungs Increase in mucus production, decrease in cilia

Reduces air flow to alveoli

Causes include bacteria, viruses, fungi, & parasites

Jim Henson, creator of the Muppets, died at age 53 from pneumonia


Respiratory Problems Tuberculosis •

Bacteria attack and cause lesions on lung tissue


Smoking Smoking is BAD •

Toxins in cigarette smoke cause and/or exacerbate all of these respiratory problems in addition with many others – including lung cancer

200 different toxins! – Tar, carbon monoxide, formaldehyde

No positive benefits associated with smoking & many documented negative health effects 60

Lecture 14 concepts - Describe functions of circulatory and respiratory systems. - List chambers of human heart – which receive blood, which pump blood? - Explain the pulmonary circuit – which blood has high / low oxygen? - List four parts of blood - describe the function of each part (liquid and cells). - Describe arteries, veins, arterioles, venules, & capillaries. - What drives blood through arteries? How are veins different? - What is cardiovascular disease? Give examples.

- Name the parts of the lymphatic system and its role/function.

- In one sentence describe cellular respiration - Explain bulk flow and diffusion for gas exchange - Chart the path that air takes into and out of the lungs - What does carbon monoxide do in the blood stream? - How does hemoglobin exchange carbon dioxide for oxygen? - What part of your body controls breathing? How do you pull in a breath? - List new vocabulary and unknown terms.


View more...


Copyright © 2017 DOCUMEN Inc.