Unit 8 - Transport in Mammals

Cardiovascular System

• Circulatory System

• includes, blood vessels, blood lymph, & heart

• Transports nutrients & O2 & hormones

• Disposal of waste

Closed Circulatory System

• Blood is contained in blood vessels

• Always in heart, arteries, veins, and capillaries

Double Circulatory System

Blood passes thru heart twice in 1 complete circuit

What is 1 Circuit?

• 1 Circuit = 2 Circulations

• Pulmonary Circulation

• Systemic Circulation

Pulmonary Circulation

Circulation thru lungs & heart

Systemic Circulation

Circulation thru other parts of body & heart EXCEPT the lungs

Open circulatory system

• Blood not w/in vessels

• Hemolymph is an analogous to blood

Single Closed Circulatory System

Blood passes thru heart once

What are blood Vessels?

• Arteries

• Capillaries

• Veins

What are Arteries?

• Carry oxygenated blood from heart

• Shorter distance from heart (higher pressure)

• Appearance:

  • Well-defined oval shape

  • Thick wall

  • Narrow Lumen

  • Folded endothelium

Arterial Wall Layers

• Tunica intima (endothelium)

• Tunica Media

• Tunica Externa (Adventitia)

What is Tunica Intima?

• Squamous epithelium cells

• one cell thick

• Smooth Surface facing lumen

What is Tunica Media?

• Thickest later

• 3 Components:

  • Collagen Fibres

  • Elastic Fibres

  • Smooth Muscle

What is tunica Externa?

• 2 Components:

  • Collagen Fibres

  • Elastic Fibres

Function of Collagen Fibres

W/stand high pressure preventing rupture of vessels

Functions of elastic fibres

• Allows vessels to stretch to w/stand high pressure

• When blood enters at low pressure it recoils giving blood small push increasing blood pressure

• Smooths out Pulsatile Flow

Systolic Pressure

Maximum Pressure of blood

Diastolic Pressure

Minimum pressure of blood

Pulsatile flow

Contracting & relaxing of arteries to smooth out blood pressure

Function of smooth muscle

• Maintain blood pressure

• Contract/relax to change volume of blood delivered

• keep blood flow moving forward

Vasodilation

Smooth muscle relax → arterioles become wider → increase blood flow

Vasoconstriction

Smooth muscle contracts → arterioles become narrow → decreasing blood flow

Elastic Arteries

• Closer to heart

• Stretch/recoil to w/stand high pressure & smooth out pulsatile flow

Muscle Arteries/Arterioles

• Further from heart

• Contract/relax controlling volume of blood flow

• Narrower so blood flow slows down

• More time for exchange of gasses and nutrients w/ tissues

What are capillaries?

• Exchange vessels, bring blood close to tissues

• Link Arteries & Veins

• Vessel Diameter = 7 micrometers

• Made of Endothelium/squamous cells

Capillary Functions

1. 1 Cell thick

   • Short Diffusion distance

2. Have pores/gaps

   • allow smaller components of blood to pass thru like H20, glucose, ions

   • Allow formation of Tissue Fluid

3. Small Lumen Diameter

   • Slows down blood flow

   • Brings RBC close to body tissue

   • Blood pressure in capillaries lowers

4. High SA

   • Network of Capillaries form Capillary bed

   • Allows more gas exchange

What are Veins?

• Carry deoxygenated blood to the heart

• low blood pressure

• Slower blood flow than arteries

• 3 Layers:

  • irregular/flattened oval shape

  • Wide lumen

  • Thin Tunica Media

  • Endothelium not wavy

Vein Features

1. pressure of Valves

   • Prevent backflow of blood

   • Ensure blood flow goes to heart

   • Close pathway when blood travels in opposite direction

2. Surrounded by skeletal muscle

   • Skeletal muscle contracts → Pushes blood to heart

What’s in Plasma?

1. H20

2. Ions

3. Proteins

4. Nutrients

5. Wastes (urea)

6. Gases

What is Tissue Fluid (TF)

• AKA intestinal fluid

• Bathes Cell

• Medium for exchange of materials between cells & blood

• TF formed from blood plasma & eventually returns to blood

How do you get TF from Plasma?

• Because different blood pressure at arterial & venous ends

• Blood pressure flows out into tissue spaces thru endothelial pores of capillaries = TF

Composition of Tissue Fluid

• H20, gases, glucose, fatty acids, urea, ions

• Smaller Proteins; low [Protein] than plasma

• low [O2] than plasma

• Some WBC’s (Phagocytes)

  • NO platelets, NO large Proteins, & NO RBC’s

How Tissue Fluid returns to Blood

• Blood pressure is low at venous ends so less stuff = TF goes back in to fill those gaps

• 90% goes into blood; other 10% turns into Lymph

Lymph

• Colorless water fluid flowing thru lymphatic system

• Carries nutrients & proteins to ur cells & tissues

WBC’s & RBC’s

both made in Bone marrow from same type of cell

What are WBC’s

• AKA Leukocytes

• Function:

  • Fighting diseases

• 2 Types:

  • Phagocytes

  • Lymphocytes

What are Phagocytes?

• produced thruout life

• Functions:

  • Patrol in blood, tissues, & organs

  • Remove dead cells & pathogen by Phagocytosis

  • Non-specific defense

  • Lobed Nuclei

  • Granular Cytoplasm (Many Vesciles)

Neutrophils

• Type of phagocyte

• Multilobed nucleus

• Have receptor proteins to identify non-self pathogens

• When infection, Large # released & accumulate at site of infection = Puss

• Short-lived (few Days)

  • Dies after eating pathogens

Monocytes

• Type of phagocyte & matures into macrophage

• Kidney bean shaped nucleus

• Larger than Neutrophils, but also has receptors

• Circulate in blood → Mature when they leave blood & alter organs

• Long-lived

• Macrophages found in liver, lungs, spleen, kidney, Lymph Nodes

Non-specific Defence

A type of defense that attacks most pathogens

Phagocytosis

When a WBC engulfs something w/ its body & gets rid of it

What are Lymphocytes