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Internal transport Csaba Bödör,

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Presentation on theme: "Internal transport Csaba Bödör,"— Presentation transcript:

1 Internal transport Csaba Bödör,
Chapter 42, (page 807-)

2 Internal transport - circulatory system
Transports nutrients, oxygen, wastes, and hormones Components: Blood – connective tissue, cells dispersed in plasma Heart – pumping organ Blood vessels – through which blood circulates Closed: Blood flows through a continuous circuit of blood vessels Interstitial fluid: tissue fluid between cells brings oxygen and nutrients into contact with cells Circulatory system also known as cardiovascular system

3 Internal transport - circulatory system
Functions of the circulatory system: Transports nutrients from the digestive system to each cell Transports oxygen from respiratory structures to the cells Transports metabolic wastes from each cell to excretory struct. Transports hormones from endocrine glands to target tissues Helps to maintain fluid balance Defends the body against invading microorganisms Helps maintain appropriate pH Helps maintain constant body temperature

4 Blood Blood – connective tissue, cells dispersed in fluid (plasma)
Production – bones, marrow cavity > red bone marrow Plasma – yellowish fluid, in which cellular elements and platelets are suspended Total circulating blood volume: 8% of the body weight, 5-6 liters in an adult ~55% of the blood volume is plasma ~45% blood cells and platelets

5 Blood Components of the plasma: ~92% water, ~7% proteins
some salts, and transported materials (gases, nutrients, water and hormones) plasma <> interstitial fluid <> intracellular fluid plasma proteins: fibrinogen, globulins and albumin fibrinogen: important role in blood clotting clotting proteins removed from plasma > serum globulins: a -globulins - some hormones and hormone transporting proteins, prothrombin, HDL b -globulins - other lipoproteins, proteins (vit, min.) g -globulins - many antibodies, immunity albumin: contributes to the blood’s osmotic pressure

6 Blood plasma proteins: also important acid-base buffers
> Help keep the pH of the blood in optimal range (7.4) Cellular components: red blood cells: transport oxygen white blood cells: defend the organism platelets: key role in blood clotting

7 Cellular Components of the Blood

8 Red Blood Cells - Erythrocytes
highly specialized cells for oxygen and CO2 transport produced in red bone marrow (vertebrae, ribs, breastbone) nucleus ejected during maturation, no nucleus in matured RBC they produce large quantities of hemoglobin > blood’s red color biconcave shape > high surface to volume ratio > diffusion 5 millions per ml > 30 trillions in whole blood

9 Red Blood Cells - Erythrocytes
life span: 120 day „old” RBCs are removed from the circulation in the liver and spleen by phagocytic cells > disassembled ~2.4 million RBCs destroyed in a second > an equal number is produced in BM RBC production is regulated by erythropoietin, hormone

10 Red Blood Cells - Erythrocytes
anemia: deficiency in hemoglobin (also in number of RBCs) insufficient hemoglobin > inadequate amounts of oxygen 3 causes: Loss of blood from bleeding Decreased production of hemoglobin Increased rate of RBC destruction

11 White Blood Cells - Leukocytes
Specialized cells to defend the body (bacteria, microorganisms) capable of independent movement, / ml some of them can slip through the vessels into the tissues Granular leukocytes and Agranular leukocytes Granular leukocytes Large, lobed nucleus, granules in the cytoplasm, 3 types Neutrophils: principal phagocytic cells (bacteria, dead cells) Eosinophils: allergic reactions, parasitic infections Basophils: allergic reactions, histamine, heparin (anticoagulant) Agranular leukocytes Rounded or kidney shaped nucleus, no granules Lymphocytes: antibody production or direct attack Monocytes: largest WBCs, monocyte > macrophage

12 Cellular Components of the Blood

13 White Blood Cells - Leukocytes

14 Platelets - Thrombocytes
key role in blood clotting in humans thrombocytes are disc shaped bits of cytoplasm enclosed by membrane with no nucleus: platelets per ml, fragments of megakaryocytes after injury they release substances essential for blood clotting they can patch damaged vessels by sticking to cut edges

15 Blood clotting Permanent clot Temporary clot Platelets adhere to collagen fibers and attract other platelets More than 30 chemical substances Hemophilia: one clotting factor is missing




19 Blood vessels 3 main types of vessels: arteries, capillaries, veins
Artery: carries blood away from heart chamber to tissues an artery enters an organ > it divides to many branches: Arterioles arterioles deliver blood into microscopic capillaries after circulating through organs capillaries merge to form veins veins channel the blood back toward the heart

20 Blood vessels Wall of an artery or vein: 3 layers (Fig 42.6!)
innermost layer: endothelium (squamous epithelium) middle layer: connective tissue and smooth muscle outer layer: connective tissue (rich in elastic and collag. fibers) arteries and veins: thick walls > no nutrient and gas exchange capillaries: only one cell thick! > exchange of materials blood > interstitial fluid > cells very extensive capillary network ( km in the body!!)

21 Blood vessels smooth muscle in arteriole wall can constrict or relax
vasoconstriction and vasodilatation > regulation of blood pressure, > distribution of blood to the tissues Regulated by the nervous system!! (recall sympathetic and parasymp.!, rerouting, redistribution of circ.)


23 Blood flow through a capillary network
„inactive tissue”, only metarterioles open „active tissue”, also capillaries open Smooth muscle Small veins

24 Human heart enclosed in pericardium (serous membrane)
Four-chambered heart separate oxygen-rich blood from oxygen-poor blood 2 atria (atrium), receive blood and 2 ventricles, pump blood into arteries Complex circulatory systems separate oxygen-rich from oxygen-poor blood valves that prevent backflow of blood

25 Human heart

26 Human heart Valves: prevent the backflow of the blood
Right atrioventricular (AV) valve (tricuspid valve) Between right atrium & ventricle Mitral valve (bicuspid valve) Between left atrium and ventricle Semilunar valves Guard the exits from the heart Cardiac muscle: striated but involuntary control

27 Human heart

28 Human heart Each heartbeat is initiated by a pacemaker
Contractions can occur independently of any nerve supply The sinoatrial (SA) node (pacemaker) initiates each heartbeat A specialized electrical conduction system coordinates heartbeats Cardiac muscle fibers are joined by intercalated discs (gap junctions) sp. conduction system > heart beat in regular rhythm Fig !!! depolarization: Ca2+

29 Human heart one complete heartbeat: 0.8 sec., > cardiac cycle
each minute the heart beat 70 times Contraction: systole Relaxation: diastole 2 heart sounds: result from heart valves closing 1. Closing the AV valves (mitral and tricuspid) > Beginning of ventricular systole 2. Closing the semilunar valves > Beginning of ventricular diastole Fig !!!

30 Human heart

31 Human heart can beat independently, but the rate is strictly regulated by the nervous system sensory receptors in the wall of certain blood vessels and heart chambers > sensitive to the blood pressure they send a message to cardiac centers in the medulla answer: sympathetic or parasympathetic nerves to SA node parasympathetic: acetylcholine, slows the heart (K+ out) sympathetic, norepinephrine, speeds the heart (Ca2+ in) signal transduction involving G-proteins stress > adrenal gland > norepinephrine, epinephrine > speed the heart

32 Human heart – cardiac output
stroke volume: the volume of blood pumped by ventricle during one beat depends mainly on venous return (amount of blood the vein deliver to heart) also on neural messages, hormones Starling’s law of the heart: if the veins deliver more blood to the heart, the heart pumps more blood cardiac output: CO= stroke volume x heart rate (number of ventricular contractions./minute) CO= 70 ml x 72 =5040 ml/min = ~5 liters/min. CO= volume of blood pumped by left ventricle into aorta in a minute It can vary with changing needs of the body (in stress: liters/min)

33 Blood pressure is the force exerted by the blood against the inner wall of the vessels it depends on the CO, blood volume, resistance to blood flow peripheral resistance: blood viscosity and friction high blood pressure : hypertension normal values 120/80 mm Hg mm of mercury Systolic pressure Diastolic pressure

34 Blood pressure

35 Blood pressure carefully regulated:
Baroreceptors - sensitive to changes in blood pressure - in walls of certain arteries when blood pressure increases: 1. message from baroreceptors to cardiac and vasomotor centers in medulla 2. Parasympathetic nerves stimulated > slow the heart rate sympathetic nerves that constrict vessels are inhibited by vasomotor centers 3. Blood pressure is reduced when blood pressure falls: sympathetic nerves > vasoconstriction >blood pressure raises again Hormones: renin – angiotensin – aldosteron !!

36 The pattern of circulation
1. Pulmonary circulation: connects the heart and lungs 2. Systemic circulation: connects the heart and all tissues The pulmonary circ. oxygenates the blood The systemic circ. delivers blood to the tissues

37 Pulmonary circulation: Systemic circulation:
The pattern of circulation Pulmonary circulation: Right ventricle pumps blood into the pulmonary arteries, Blood circulates through pulmonary capillaries in the lung Blood is conducted to the left atrium by a pulmonary vein (!) Systemic circulation: Left ventricle pumps blood into the aorta Aorta branches into arteries leading to the body organs Blood flows through capillary networks within various organs Blood flows into veins that conduct it to the superior or inferior vena cava Blood returns to the right atrium

38 Human heart

39 The pattern of circulation
Coronary arteries: Supply the heart muscle with blood Page: 825, fig: 42-17 … Carotid arteries, jugular veins, etc. …

40 The lymphatic system In addition to circulatory system: an accessory circulatory system, the lymphatic system Roles: a, to collect and return interstitial fluid to the blood b, to launch immune response c, to absorb lipids from the digestive tract Components: a, lymphatic vessels An extensive network, conducts lymph (fluid formed from interstitial. fluid) b, lymph tissue (type of connective tissue, with lymphocytes) Is organized into small lymph nodes Tonsils, thymus gland, spleen > lymphatic system „dead end” lymphatic vessels almoust in all body tissues (fig 42.18) Interstitial fluid enters lymphatics > lymph

41 The lymphatic system Lymphatic system and fluid homeostasis
Lymph circulates through lymph nodes > bacteria filtered out All lymphatic vessels > thoracic duct and right lymphatic duct > join the circulatory system in the shoulder region (subclavian veins) Lymphatic system and fluid homeostasis Fluid movement between blood and interst. fluid: blood pressure and osmotic pressure (B, IF) Fig 42.20

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