B L O O D P A R T 1

Cardiovascular System

Homework

Lab this week

Endocrine presentations

No PreLab this week

Due Monday 2/25/13

HW 13-14: Endocrine System HW 1

HW 17: Endocrine System HW 3

Introduction

Circulation

Blood vascular

Blood

Heart

Blood vessels

Lymphatic system

Lymph

Lymph vessels

Lymph nodes

Blood

Formed Elements

Cellular portion

Fluid portion

Arterial versus venous

Blood

~8% of body weight

Average volume

Males : 5–6 L

Females: 4–5 L

Blood

Viscosity

Color

pH

7.35–7.45

Temperature

38C (99 F)

Functions of Blood

1. Transport

O2 and carbon dioxide

Nutrients

Metabolic wastes

Hormones and enzymes

Functions of Blood

2. Regulation

Body temperature

pH

Water content of cells

Functions of Blood

3. Protection against Blood loss

Plasma proteins and platelets initiate clot formation

Infection (immune response)

Antibodies

WBC’s

Structure of Blood

Formed elements 45%

Plasma 55%

Copyright © 2010 Pearson Education, Inc. Figure 17.1

1 Withdraw

blood and place

in tube.

2 Centrifuge the

blood sample.

Plasma • 55% of whole blood • Least dense component Buffy coat • Leukocytes and platelets • <1% of whole blood Erythrocytes • 45% of whole blood • Most dense component

Formed

elements

Plasma

Water 90%

Proteins 7-9%

Albumin

Viscosity and osmolarity

Globulins

Transport and immunity

Fibrinogen

Clotting

Plasma

Electrolytes

Na+, K+, Ca2+, Cl–, HCO3–

Nutrients

Glucose, carbohydrates, amino acids, lipids

Gases

O2 and CO2

Wastes

Lactic acid, urea, ketones, uric acid

Formed Elements

Erythrocytes

No nuclei or organelles

Leukocytes

5 types

Granular

Agranular

Thrombocytes

Cell fragments

Formed Elements

General

Most survive in the bloodstream for only a few days

RBC’s = 120 days

Most blood cells do not divide and originate in bone marrow

Figure 17.2

Platelets

Neutrophils Lymphocyte

Erythrocytes Monocyte

Erythrocytes

Appearance Biconcave discs

Non-nucleated

8 nm in diameter

Figure 17.3

2.5 µm

7.5 µm

Side view (cut)

Top view

Erythrocytes

Properties Filled with hemoglobin (Hb) for gas transport

Major factor contributing to blood viscosity

Survive 120 days

Hematocrit Males 47%

Females 42%

Erythrocytes

Gas transport Biconcave shape

Hemoglobin 33% of weight

No mitochondria

ATP production is anaerobic (no O2 is used in generation of ATP)

Erythrocytes

Hemoglobin structure

Globin: protein

Heme: iron

Each Hb molecule can transport 4 O2

Each RBC has about 250 million Hb molecules!

Erythrocytes

Hemoglobin roles

O2 loading in the lungs

O2 unloading in the tissues

CO2 loading in the tissues

Hematopoiesis

Blood cell formation

Red bone marrow of axial skeleton, girdles and proximal epiphyses of humerus and femur

Erythropoiesis

Spongy bone

Sternum, ribs, cranium

Epiphyses

Femur and humerus

Vertebral bodies

Figure 17.5

Stem cell

Hemocytoblast Proerythro- blast

Early erythroblast

Late erythroblast Normoblast

Phase 1

Ribosome synthesis

Phase 2

Hemoglobin accumulation

Phase 3

Ejection of nucleus

Reticulo- cyte

Erythro- cyte

Committed

cell

Developmental pathway

Erythropoiesis

Erythropoiesis

Regulation

Too few RBCs leads to tissue hypoxia

Too many RBCs increases blood viscosity

Balance between RBC production and destruction depends on

Hormonal controls (renal erythropoietic factor)

Adequate supplies of iron, amino acids and B vitamins

Erythropoiesis

Hormonal control

Hypoxemia kidney’s release REF plasma protein converted to EPO RBC production stimulated

Erythropoiesis

Effects of EPO

More rapid maturation of committed bone marrow cells

Increased circulating reticulocyte count in 1–2 days

Figure 17.6

Kidney (and liver to a smaller extent) releases erythropoietin. Erythropoietin

stimulates red bone marrow.

Enhanced erythropoiesis increases RBC count.

O2- carrying ability of blood increases.

Homeostasis: Normal blood oxygen levels

Stimulus:

Hypoxia (low blood

O2- carrying ability)

due to

• Decreased RBC count

• Decreased amount of hemoglobin

• Decreased availability of O2

1

2

3

4

5

Erythrocytes

Fate

Life span

Old RBCs become fragile and Hb begins to degenerate

Macrophages engulf dying RBCs in the spleen