Tissues Flashcards
Histology:
Systematic study of tissue types
Pathology:
Study of causes and effects of diseases
Main tool is Hematoxylin and Eosin stain (H&E):
- Nuclei- Blue
- Cytoplasm- Red
Epithelium Function
Covering
Lining
Glandular
What is Epithelium Classified by?
Arrangement
Morphology
Epithelium Blood supply:
Avascular (no blood supply) –sits on basement membrane which aids in nutrient and waste exchange
What are the 2 types of glandular in the Epithelium and their functions:
Exocrine:Secrete substances into ducts which empty onto epithelial surfaces
Endocrine: Secrete substances that diffuse into bloodstream (no ducts)
Simple meaning:
One layer of cells
Stratified meaning:
More than one layer of cells
Squamous meaning:
Cells are wider than tall (plate-like) – “squashed”
Cuboidal meaning:
Cuboidal—cells are as wide as tall, like cubes
Columnar meaning:
Columnar—cells are taller than they are wide, like columns
Simple squamous Epithelium Location and function:
Function: diffusion & filtration
Location: kidney glomeruli, blood vessels, lymphatic vessels
Simple Cuboidal Epithelium Location and function:
Function: secretion & absorption
Location: Kidney tubules
Simple columnar Epithelium Location and function:
Function: absorption & secretion
Location: Stomach, intestines, gallbladder, uterus
Pseudo-stratified columnar Epithelium Location and function:
Function: secretion
Location: trachea
Stratified squamous Epithelium Location and function:
Function: protection
Location: esophagus, mouth, urethra, epidermis
Stratified Cuboidal Epithelium Location and function:
Function: protection
Location: largest ducts if sweat glands, mammary glands, salivary glands
Stratified Columnar Epithelium Location and function:
Function: protection & secretion
Location: male urethra
Transitional Epithelium Location and function:
Function: stretches
Location: lines the ureters, bladder and parts of urethra
Connective Tissue Function:
Connective Tissue is the most diverse and abundant tissue type. Connective tissue makes up a variety of physical structures including, tendons, blood, cartilage, bone, adipose tissue, and lymphatic tissue.
Main classes of Connective Tissue:
Connective tissue proper
Cartilage
Bone
Blood
Connective Tissue Terminology:
BLAST: roughly meansimmaturecell or tissue and isinvolved in making something, in this case, the matrix.
CYTE: means CELL and is maintaining or involved with the final product.
CLAST: Breakdown the extracellular matrix in connective tissue.
Cells found in Connective Tissue
Fibroblasts: cells in connective tissue that make fibrous proteins and secrete the molecules that form ground substances and collagen.
Chondroblasts: secrete matrix in cartilage (to make chondrocytes).
Osteoblasts: secrete matrix in bone to help create bone.
Blood cells: don’t produce matrix. In blood, the ECM is plasma.
Fat cells: energy storage, cushions, insulation
What are the Structural Elements of Connective Tissue:
- Extracellular Matrix (ECM)
- Ground Substances
- Fibres
Extracellular Matrix (ECM):
Ground substance that contains many different sugar-proteins and large sugars.
Extracellular matrix is composed of ground substance (ranges from gel-like to hard in texture) and protein fibers (collagen, reticular, elastic). It provides cushioning and protection e.g. kidneys, which are surrounded by fat.
Ground Substances of Connective Tissue:
Hyaluronic Acid: Polysaccharide that acts as a lubricant when rubbed and is sticky when touched.
Proteoglycan: Protein and polysaccharide that traps water.
Adhesive molecules: Hold Proteoglycan aggregates together. Are named with the suffix -nectin.
Fibres of Connective Tissue
Collagen fibres: very strong, similar to a coiled rope of 3 polypeptide chains. Thickest and strongest of the 3 fibres.
Reticular fibres: Very fine, short, branching collagen fibres. Not as strong as most collagen fibres, but networks of these fibres fill space between tissues and organs. Found in organs that have lots of mesh-like internal structure. The spleen for example is full of these and acts like a filter.
Elastic fibres: stretch and recoil and contain a rubberlike protein called elastin, form a large, interwoven meshwork of spring-like molecules that extend through entire tissue.
11 Classification of Connective Tissues:
- Loose Connective Tissue- Areolar tissue
- Adipose
- Reticular
- Dense Connective Tissue, Regular
- Dense Fibrous, Irregular
- Compact (Cortical)Bone
- Cancellous Bone
- Hyaline Cartilage
- Fibrocartilage
- Elastic Cartilage
- Fluid
Muscle Tissue Function:
- Movement
What is muscle tissue classified by
- Morphology
- Function
Nervous Tissue Function:
Transmission of impulses
What is Nervous tissue classified by
- Location
- Morphology
- Function
What are Membranes
Body membranes are thin sheets of tissue that cover the body, line body cavities, and cover organs within the cavities in hollow organs. They can be categorized into epithelial and connective tissue membranes.
What are the 6 types of Membranes:
- Epithelial Membranes
- Cutaneous Membrane
- Mucous Membranes
- Serous Membranes
- Connective Tissue Membranes
- Synovial Membranes
Epithelial Membranes:
Epithelial membranes consist of epithelial tissue and the connective tissue to which it is attached.
Cutaneous
Mucous
Serous
Cutaneous Membrane:
Cutaneous membrane=skin.
Primary role is to help protect the rest of the body’s tissues and organs from physical damage such as abrasions, chemical and biological damage.
Mucous Membranes:
Mucous membranes are epithelial membranes that consist of epithelial tissue that is attached to an underlying loose connective tissue. These membranes, sometimes called mucosae, line the body cavities that open to the outside. The entire digestive tract is lined with mucous membranes. Other examples include the respiratory, excretory, and reproductive tracts.
Serous Membranes:
Serous membranes line body cavities that do not open directly to the outside, and they cover the organs located in those cavities. Serous membranes are covered by a thin layer of serous fluid that is secreted by the epithelium.
Serous fluid lubricates the membrane and reduces friction and abrasion when organs in the thoracic or abdominopelvic cavity move against each other or the cavity wall.
Serous membranes have special names given according to their location.
1. Pleural
2. Pericardial
3. Peritoneal
4. (visceral and parietal)
Connective Tissue Membranes
Connective tissue membranes contain only connective tissue. Synovial membranes and meninges belong to this category.
Synovial Membranes
Synovial membranes are connective tissue membranes that line the cavities of the freely movable joints such as the shoulder, elbow, and knee. Like serous membranes, they line cavities that do not open to the outside. Unlike serous membranes, they do not have a layer of epithelium. Synovial membranes secrete synovial fluid into the joint cavity, and this lubricates the cartilage on the ends of the bones so that they can move freely and without friction.
Meninges
The connective tissue covering on the brain and spinal cord, within the dorsal cavity, are called meninges. They provide protection for these vital structures.
Different types of Tissue repair:
If a cell is unable to adapt to change, irreversible injury leads to cell death
Necrosis- unprogrammed cell death
Apoptosis- programmed cell death
Autolysis- self-digestion
Heterolysis- digestion from outside the cell
Tissue Repair Phases:
Inflammation: Body’s natural response to trauma
Proliferation: Rebuild with new healthy tissue
Maturation: Remodeling and healing
Acute Inflammation
- Vascular dilatation
- Endothelial activation
- Neutrophil activation and migration
Vascular dilatation
Relaxation of vascular smooth muscle leads to engorgement of tissue with blood (hyperaemia)
Endothelial activation
Increased endothelial permeability allows plasma proteins to pass into tissues
Expression of adhesion molecules on the endothelial surface mediates neutrophil adherence
Production of factors that cause vascular dilatation e.g. Histamine (dilation), Serotonin (permeability)
Healing by Fibrosis (scar formation):
- Substantial damage to the connective tissue framework and/or the tissue lacks the ability to regenerate specialized cells
- Structural integrity is re-established (lacking specialized cells, usually architectural distortion)
