Transport WIP Flashcards
Capillaries
Blood flows through tissues in capillaries
Have permeable walls that allow exchange of materials between cells in tissue and blood in capillary
Small diameter which allows passage of only one blood cell at a time
Capillary wall is epithelial to minimize diffusion
Surrounded by basement mb which is selectively permeable
May contain pores to further aid in transport of materials between tissue fluid and blood
Function of Capillaries
Exchange materials between tissue cells and blood travelling in low pressure
Arteries split into arterioles which split into capillaries, decreasing pressure
Branching into capillaries ensures that blood is moving slowly, cells are near a blood supply, and that capillaries will combine into venules which will turn into large veins
Types of Capillary Structure
Some can be continuous with endothelial cells held together tightly to limit permeability
Some can be fenestrated when specialized for absorption
Some can be sinusoidal and have open cells between cells and be permeable to large molecules
Structure of Artery
Convey blood at high pressure from ventricles to body tissues
Have muscle cells and elastic fibres in walls. Thick walls contain an outer layer of collagen to resist high tensile strength an prevent it from rupturing
Muscle and elastic fibres assist in maintaining blood pressure between pump cycles
Structure of Vein
Collect blood at low pressure from body tissues and return it to heart’s atria
Valves in veins and heart ensure circulation of blood by preventing backflow
Walls in Arteries and Veins
Tunica Externa: Outer coat of rough collagen fibres and elastic tissue
Tunica Media: Thick layer of smooth muscle cells, elastic tissue and collagen fibres
Tunica Intima: Endothelium made of single layer of cells with extra elastic tissue near heart
Lumen: Space inside artery which blood flows through, usually narrow
Function of Arteries, Capillaries and Veins
Carry blood from ventricles to body tissues
Collect blood from arteries and send back to veins / allow exchange of materials between tissue cells and capillary blood
Collect blood from body tissues and return it to heart’s atria
Blood Pressure of Arteries, Capillaries and Veins
High
Low
Low
Wall of Arteries, Capillaries and Veins
Thick to withstand high pressure and prevent bursting
Very thin one cell thick wall to allow rapid diffusion and movement / Have permeable walls to allow exchange of materials between tissue cells and capillary blood / have pores in wall to allow phagocytes to enter and leave tissue
Have thinner walls because pressure is low
Wall Layers of Arteries, Capillaries and Veins
Three
One
Three
Muscle Cells and Elastic Fibres of Arteries, Capillaries and Veins
Many to help wall stretch and withstand high pressure / can also contract to narrow lumen to increase blood pressure and pressure between pumps
Absent
Few because pressure is low and no pulse
Lumen of Arteries, Capillaries and Veins
Narrow which results in fast moving blood
Very narrow to penetrate all parts of tissues for bigger surface area
Wide which results in slow moving blood
Valves of Arteries, Capillaries and Veins
Absent
Absent
Present
Risk Factors of Blocking of Coronary Arteries
A DOGS DES
Age
Diseases
Obesity
Genetics
Sex
Diet
Exercise
Smoking
Atherosclerosis
The hardening and narrowing of the arteries due to the deposition of cholesterol
