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?