The Circulatory and Respiratory Systems

Transcription

1 The Circulatory and Respiratory Systems Chapter 37 A beginning

2

3 Circulatory System-Functions Helps maintain homeostasis by controlling the surroundings of cells Heart: heart and body circulation, heartbeat Vessels:Individual organ and cells supply and exchange of materials

4 The Heart Pericardium: protective sac around the heart Myocardium: the actual heart muscle, non striated cardiac muscle, does not fatigue

5 Heart Anatomy

6 Heart Anatomy Atria: thin walled, collection for blood returning to heart Ventricles: thick, powerful walls, pump blood to organs Septum: thick wall between the ventricles

7 Heart Anatomy Valves: Prevent backflow of blood into the chambers Nodes: act as both muscle and nervous tissue, control heartbeat Pacemaker: Sinoatrial Node

8 Circulation Through Body

9 Circulation Through Body Pulmonary Circulation: Flow of blood from the right side of the heart to the lungs and back Systemic Circulation: Flow of blood from the left side of the heart to the body and back

10 Blood Flow Through the Heart Stage 1: Blood returning from the body in the Vena Cava enters the Right Atrium, carrying CO 2, At the same time O 2 rich Blood returning from lungs enters Left Atrium from Pulmonary Vein

11 Blood Flow Through the Heart Stage 2: The Atrioventricular Node forces the Atrias to contract, Blood passes by the Atrioventricular valves and empties into the Ventricles

12 Blood Flow Through the Heart Stage 3: AV valves close, Sinoatrial Node sends signal for ventricles to contract

13 Blood Flow Through the Heart Stage 4: The Semilunar valves open as the ventricles contract. The blood from the Right Ventricle is pushed into the Pulmonary Artery (Pulmonary Circuit) to lungs for gas exchange

14 Blood Flow Through the Heart Stage 4: The blood from the Left Ventricle is forced out the Aorta to deliver O 2 to the systemic circuit

15 The Blood Vessels As blood flows through the circulatory system, it moves through three types of blood vessels: Arteries, Capillaries, and Veins

16 Arteries Large, carry blood from heart, have thick walls made up of three layers to handle high pressure

17 Capillaries Smallest of the blood vessels, one cell layer thick for exchange of chemicals with fluids

18 Veins Thin walled, return blood to heart, blood is moved by muscle contraction and valves to prevent backflow (because is going against gravity)

19 Blood Pressure When the heart contracts it produces a hydrostatic force against a vessel wall, called blood pressure Higher in Arteries, keeps blood flowing

20 Blood Pressure Systolic Pressure: the force in the arteries when the ventricles contract Diastolic Pressure: the force in the arteries when the ventricles relax

21 Blood

22 Blood Connective tissue with cells suspended in plasma Contains: Plasma (Electrolytes, plasma proteins), Erythrocytes (RBC s), Leukocytes (WBC s), and Platelets

23 Plasma 90% water Electrolytes: inorganic salts, maintain osmosis, controlled by kidneys Plasma Proteins: help buffer blood Also: nutrients, metabolic wastes, respiratory gases, hormones

24 Erythrocytes Also called Red Blood Cell s Most numerous cells, 5x10 6 in a ml of blood Transport O 2, shaped like discs Contain Hemoglobin, which uses Iron to bind to 0 2

25

26 Erythrocytes Produced in Bone Marrow Lack Nuclei Disc shape allows them to be flexible in small capillaries

27

28 Leukocytes Also called White Blood Cells Produced in Red Marrow, contain Nuclei Function is to protect, they attack foreign substances or organisms

29

30

31 Leukocytes Number of cells is increased during infection Some engulf cells (Phagocytes), others secrete chemicals (Basophils)

32 Platelets Lack nuclei Function in blood clotting Are fragments of large cells in bone marrow Sticky structure allows them to adhere, and help stop flow of blood

33

34 Inactive Platelets

35 Active Platelets

36 The Lymphatic System Returns fluid (called Lymph) to the blood that leaks out of the vessel walls and aids in body defense, help absorb fat in small intestine Lymph Nodes: specialized swellings that filter, and attack viruses and bacteria

37 The Respiratory System

38 The Respiratory System A breath of fresh air Respiration: the process in which O 2 and CO 2 are exchanged between cells, the blood, and air in the lungs Consists of: Nose, Pharynx, Larynx, Trachea, Bronchi, and Lungs

39 Anatomy of Respiration (Figure on page 957) Pharynx: passage way for air/food at the back of the throat Larynx: contain vocal cords Trachea: connects Pharynx to the Bronchi, called the windpipe, protected by epiglottis

40 Anatomy of Respiration Bronchi: large passageways in chest cavity, each leads to a lung, divide in smaller bronchioles Alveoli: tiny air sacs, smallest vesicle in lungs, grouped in clusters, surrounded by thin-walled capillaries, increase surface area for gas exchange

41 Gas Exchange Occurs in Alveoli, O 2 dissolves in surfactant, and diffuses across the cell membrane, CO 2 in capillaries diffuses into the lungs Efficient: removes 30% of O 2 in every breath

42 Breathing Controlled by Medulla Oblongata in brain Movement of Air in and out of lungs, controlled by the diaphragm

43 Breathing When the diaphragm contracts, pulls the chest cavity and expands it, the negative pressure created forces air into the lungs, filling the passageways

44 Breathing When the diaphragm relaxes, the pressure in lungs is greater, so air is pushed out, a passive event, can be increased using muscles around the chest cavity