Tissues - Slide 13 Overview

Tissues - Slide 13

• Epithelial tissues cover body surfaces
• Types: epithelial (skin, airways) and endothelial (blood vessels)
• Functions: absorption, secretion, transport, and protection
• Structures: layers and cell shapes
  • Layer arrangement: simple (single layer), pseudostratified (single layer, varying heights), stratified (multiple layers)
  • Cell shapes: squamous (flat), cuboidal (cube-shaped), and columnar (tall rectangular)
• Pseudostratified layer of cells: Nuclei at the basal end of the cells
  • Nuclei at different levels. Very tightly packed

Connective Tissue

• Most abundant tissue type
• Characterized by low cell density and large extracellular matrix
• Types
  • Loose connective tissue: example, adipose tissue (fat storage)
  • Dense regular: found in ligaments and tendons (parallel fibers)
  • Dense irregular: found in dermis and capsules (randomly arranged fibers)
  • Supportive connective tissues
    • Cartilage: provides support and flexibility
    • Bone: provides structural support and mineral storage

Fluid Connective Tissue

• Blood and lymph transport nutrients, oxygen, and immune cells
• Components: red blood cells (erythrocytes), platelets (thrombocytes), and white blood cells (leukocytes).
• Leukocytes (white blood cells) further classified based on presence/absence of granules into agranulocytes and granulocytes and based on function

Muscle Tissues

• Types: skeletal (voluntary), smooth (involuntary), and cardiac (involuntary)

Nervous Tissue

• Responsible for sensing stimuli and transmitting signals
• Components: neurons (dendrites, cell body, axon) and neuroglia (oligodendrocytes and Schwann cells)

Organs and Organ Systems

• Organs are structures made of tissues
• Organ systems are groups of organs performing coordinated functions.
• Major organ systems: cardiovascular, respiratory, nervous, skeletal, muscular, integumentary, endocrine, lymphatic, digestive, urinary, and reproductive

Cardiovascular System

• Coronary artery disease and arrhythmias
• Functions: transport oxygen and nutrients, remove waste, remove metabolic products, regulate body temp Blood Circulation: Humans have approximately 5 liters of blood
• Proximity of blood vessels to cells that facilitates diffusion of oxygen, nutrients, and waste
• Pulmonary circuit: deoxygenated blood to lungs
• Systemic circuit: oxygenated blood to body
• Pulmonary vessels: transport blood to and from lungs
• Systemic vessels: transport blood to and from the body
• Arteries: carry blood away from the heart
• Veins: carry blood back to the heart
• Chambers, valves and pathways for blood flow
• Cardiac cycle: Includes diastole and systole
• Blood pressure is highest in the arteries and lowest in the veins

Cardiovascular System - Electrical

• Autorhythmic cells: generate electrical impulses that control heart rate (nodal tissues: SA node, AV node, bundle of His)
• Myocardial contractile cells: muscle cells

ECGs and Diagnosis

• ECGs measure electrical activity of the heart's conduction system
• Detect arrhythmias, heart blocks, and myocardial infarction.

Pacemakers and ICDs (Implantable Cardioverter Defibrillators)

• Used to treat abnormal heart rhythms
• Pacemakers regulate heart rate; ICDs deliver electrical impulses to correct arrhythmias

Cardiac Cycle Thermodynamics

• Blood pressure highest in arteries and lowest in veins
• Phases (systole/diastole): ventricular filling, atrial contraction, ventricular contraction, and ventricular relaxation

Blood Rheology

• Study of blood's characteristics as a fluid (viscosity, yielding stress)
• Factors influencing blood viscosity
• Key components involved in blood rheology
  • Erythrocytes, plasma, white blood cells, and platelets
  • Hematocrit, fibrinogen

Left Ventricular Heart Failure

• Reasons for failure
• Symptoms of failure

Left Ventricular Assist Device (LVAD)

• Mechanical circulatory support for heart failure
• Used as a bridge to transplant or to recovery