The Circulatory System: BLOOD Saladin - Chapter 18.1 – 18.5
The Circulatory System: BLOOD
Saladin - Chapter 18.1 – 18.5
Objectives!
Describe the functions and major components of the circulatory system
Describe the components and physical properties of blood
Describe the composition of blood plasma
Explain the significant of blood viscosity and osmolarity
Describe in general terms how blood is produced
FUNCTIONS
Functions of the Circulatory System TRANSPORT PROTECTION REGULATION
CIRCULATORY SYSTEM
Consists of: Heart Blood vessels Blood
Cardiovascular system:▪ Heart▪ Blood vessels
ANIMATION
http://www.youtube.com/watch?v=57wrBvyp4jQ&noredirect=1
Circulatory System Animation
Function: TRANSPORT
FUNCTION: transport explained
The blood carries O2 from the lungs to body’s tissues, while it picks up CO2 from those tissues and carries it to the lungs for removal
It picks up nutrients from the GI tract and delivers to all of the body’s tissues
Carries metabolic wastes to the kidneys for removal
FUNCTION: transport explained
Carries hormones from endocrine cells to target cells
Transports variety of stem cells from bone marrow and other origins to the tissues where they lodge and mature
Helps to regulate body temp by carrying heat to the body surface for removal
FUNCTION: protection
Blood plays role in inflammation, a mechanism for limiting the spread of infection
WBCs destroy microorganisms and cancer cells
Antibodies and other blood proteins neutralize toxins and help destroy pathogens
Platelets secrete factors that initiate blood clotting and other processes for minimizing blood loss
Protection - example
FUNCTION: regulation
By absorbing or giving off fluid under different conditions, the blood capillaries help to stabilize fluid distribution in body
By buffering acids and bases, blood proteins help to stabilize the pH of the extracellular fluids
BLOOD COMPONENTS
Plasma
Formed Elements
FORMED ELEMENTS (7)
Erythrocytes Platelets Leukocytes (WBCs)
Granulocytes▪ Neutrophils▪ Eosinophils▪ Basophils
Agranulocytes▪ Lymphocytes▪ Monocytes
GENERAL PROPERTIES
Formed elements – to -plasma A ratio seen by spinning blood sample within a
centrifuge
Erythrocytes – densest, therefore sink to bottom▪ Make up ~45% of the total volume = hematocrit
WBC’s and platelets make up a narrow cream- or buff- colored zone, the buffy coat, just above the RBCs, ~1%
At top of tube is pale yellow plasma, ~55%
CHECKPOINT
Name the different types of Leukocytes Ans – in the margin
What are 3 protective mechanisms for keeping the pH of the blood at homeostasis? Ans - Respiratory system, carboxylic
buffering, renal system
BLOOD PLASMA
A complex mixture of water, proteins, nutrients, electrolytes, nitrogenous wastes, hormones, and gases.
SERUM – what is left when the blood blots and the solids are removed
Nearly identical to plasma except for the absence of the clotting protein fibrinogen
BLOOD PLASMA
Protein
Most abundant plasma solute by weight Play role in clotting, defense, and transport of other solutes
(iron, copper, lipids, and hydrophobic hormones
3 major categories of proteins▪ Albumins▪ Globulins▪ Fibrinogen
Nitrogenous Wastes Toxic end products of catabolism Urea most abundant
BLOOD PLASMA: protein categories
Albumins Smallest and most abundant plasma protein Serves to transport various plasma solutes and
buffer the pH of the blood plasma Make a major contribution to 2 physical
properties of blood▪ Viscosity▪ Osmolarity
Globulins
Fibrinogen
Albumins
Globulins Divided into 3 subclasses; from smallest to largest molec.
wt▪ Alpha▪ Beta▪ Gamma –
Play various roles in solute transport, clotting, and immunity
Fibrinogen
BLOOD PLASMA: protein categories
Albumins
Globulins
Fibrinogen A soluble precursor of fibrin, a sticky
protein that forms the framework of a blood clot
BLOOD PLASMA: protein categories
Transports nutrients absorbed by the digestive tract includes glucose (blood sugar), amino acids, fat,
cholesterol, phospholipds, vitamins, and minerals
Transports some of the oxygen and carbon dioxide carried by blood
Carries substantial amount of dissolved nitrogen Free nitrogen normally has no physiological role in
the body, but it becomes important under circumstances such as scuba diving/aviation
BLOOD PLASMA: general properties
BLOOD PLASMA: electrolytes
Sodium ions constitute ~90% of the plasma cations.
Sodium is more important than any other solite for the osmolarity of the blood
Blood Viscosity
Viscosity – resistance of a fluid to flow, resulting from the cohesion of particles
RBC or protein deficiency reduces viscosity, causes blood to flow too easily
Puts strain on the heart
Blood Osmolarity
The total molarity of those dissolved particles that cannot pass through the vessel wall
Substances must pass between the bl stream and tissue fluid thru capillary walls Depends on osmosis
Hematopoiesis – RBC formation
Occurs in red bone marrow
All blood cells are derived from a common stem cell (Hemocytoblast)
How Blood is Produced
Life of an RBC
Unable to divide, grow, or synthesize proteins
Wear out in 100-120 days
When worn out, are eliminated by phagocytes in the spleen or liver
Lost cells are replaced by division of stem cells
Negative feedback of Correction of Hypoxemia by Erythropoiesis
RBC, platelet, WBC
CHECKPOINT
What is the name of the cell that all blood cells originate from?
What is the process called when red blood cells are produced?
What type of ions constitute most of blood plasma, and have a significant role in osmolarity?