Tissues etc notes

Histology

Histology

The study of tissues.

Biopsy

The removal of living tissue for microscopic examination.

Connective tissue

Tissue that transports, protects, supports, and binds tissues and organs; stores energy as fat; provides immunity.

Muscular tissue

Tissue that produces movement via contraction and generates body heat.

Epithelial tissue

Tissue that covers body surfaces, lines hollow organs, body cavities, and ducts; forms glands.

Nervous tissue

Tissue that detects changes in the body and responds by generating nerve impulses.

Intercellular junctions

Various types of connections between adjacent cells.

Tight junctions

Junctions that create a leakproof seal between cells.

Adherens junctions

Junctions that make an adhesion belt to prevent tissues from separating.

Desmosomes

Junctions that act as "spot welds" to connect adjacent cells.

Hemidesmosomes

Junctions that join cells to the basement membrane.

Gap junctions

Pores that allow small substances to pass between cells, enabling rapid communication.

Germ layers

The different layers of cells from which each tissue type develops.

Simple epithelia

Epithelia composed of a single thin layer of cells.

Stratified epithelia

Epithelia composed of two or more layers of cells.

Endocrine glands

Ductless glands that secrete hormones directly into the blood vessels.

Exocrine glands

Glands that secrete substances through ducts to the epithelial surface.

Skeletal muscle

Muscle under voluntary control that contracts to pull on bones or skin.

Cardiac muscle

Muscle under involuntary control found in the myocardium of the heart wall.

Smooth muscle

Muscle under involuntary control found in the walls of hollow organs.

Connective tissue

The most abundant and widely distributed tissue type in the body.

Ground substance

The non-living extracellular matrix of connective tissue.

Protein fibers

Collagen, elastic, and reticular fibers found in the extracellular matrix of connective tissue.

Loose connective tissue

Connective tissue that includes areolar, adipose, and reticular tissues.

Dense connective tissue

Connective tissue that includes regular, irregular, and elastic tissues.

Cartilage

Connective tissue that includes hyaline, fibrocartilage, and elastic cartilage.

Bone (osseous) tissue

Connective tissue that includes compact and spongy bone.

Liquid connective tissue

Connective tissue that includes blood and lymph.

Tissue damage

Injury to living tissue caused by trauma, disease, or wear and tear.

Physical trauma

Injury to living tissue caused by an external agent.

Strains and sprains

Injuries caused by wear and tear.

Regeneration

The replacement of destroyed tissue by the same kind of cells.

Mesenchymal cells

Multipotent adult stem cells that can differentiate into many types of tissue cells needed for regeneration.

Fibrosis

The replacement of destroyed tissue by dense (fibrous) connective tissue, forming scar tissue.

Fibroblasts

Cells responsible for fibrosis and the production of collagen.

Connective tissue repair

The process of repairing damaged connective tissue.

Haematopoietic stem cells

Stem cells found in red bone marrow that can make blood cells.

Limited tissue repair

The limited capacity for tissue repair in nervous, muscle, dense connective tissue, and cartilage tissues in adults.

Intrinsic hypocellularity

Lack of cells within a tissue or structure.

Dense extracellular matrix

A tightly packed network of molecules outside of cells that restricts cell movement and proliferation at an injury site.

Sprain

The stretching or tearing of ligaments, which affects joint reinforcement and range of motion.

Grade 1 sprain

Ligament is stretched but not torn.

Grade 2 sprain

Ligament is partially torn, accompanied by inflammation and bruising.

Grade 3 sprain

Ligament is completely torn or ruptured, causing inflammation and bruising.

Joint instability

Joints become unstable due to severe sprains, leading to bones moving out of alignment and an extended range of motion.

Bone fractures

Breaks in bones.

Closed fracture

A fracture that does not penetrate the skin.

Open fracture

A fracture where the broken bone penetrates through the skin.

Reduction and immobilization

Treatment for bone fractures involving realignment and immobilization of the broken bone.

Haematoma

A blood-filled swelling that forms at the site of a bone fracture.

Fibrocartilage callus

The splinting of a bone fracture by fibrocartilage, which is later replaced by a bony callus.

Bony callus

A solid mass of spongy bone that replaces the fibrocartilage callus during bone fracture repair.

Permanent patch

The remodeling of the bony callus into compact bone to form a permanent fix for the bone fracture.

Skeletal muscle repair

Skeletal muscle cells cannot divide but can lay down new protein and enlarge (hypertrophy) to repair damage.

Satellite cells

Stem cells found in skeletal muscle that divide and fuse with existing muscle fibers to regenerate and repair damaged muscle tissue.

Cardiac muscle repair

Cardiac muscle lacks stem cells for tissue regeneration and has limited repair capacity.

Smooth muscle repair

Smooth muscle regenerates from pericytes, which are stem cells found in some blood vessels.

Myofibrosis

Replacement of muscle tissue by scar tissue, reducing muscle functionality.

Strain

Stretching or tearing of skeletal or cardiac muscle fibers due to excessive force or stretching beyond limits.

Grade I strain

Mild strain with a few stretched or torn muscle fibers, maintaining normal muscle strength.

Grade II strain

Moderate strain with more injured fibers, inflammation, loss of strength, and possible bruising.

Grade III strain

Severe strain that tears the muscle all the way through, resulting in complete loss of muscle function, inflammation, and bruising.

Nervous tissue repair

Nerve cells cannot divide and replace damaged cells, but the peripheral nervous system (PNS) has some capacity for repair and regeneration.

Gliosis

Formation of scar tissue composed of glial cells in the central nervous system (CNS) as a response to tissue damage.

Epithelial tissue repair

Epithelial tissues have a high regenerative capacity through the division and differentiation of stem cells or parenchymal cells.

Exocrine glands

Glands that continuously lose cells and replace them with new ones through regeneration, such as the liver and sebaceous glands.

Endocrine glands

Glands that contain stem cells capable of tissue regeneration, such as the pituitary, adrenal, and pancreas.

Open wound healing

The healing process for wounds that extend to the dermis and subcutaneous layer, resulting in scar tissue formation.

Epidermal wound healing

Healing of superficial wounds that only affect the epidermis, usually leading to a return to normal function.

Inflammation and haemostasis

The initial stage of wound healing involving bleeding stoppage, inflammation, and clot formation.

Organisation and blood supply restoration

The stage of wound healing where new capillaries grow, granulation tissue replaces the blood clot, and epithelium begins to regenerate.

Regeneration and fibrosis

The final stage of wound healing involving the regeneration of surface epithelium and the formation of scar tissue.

Burns

Tissue damage caused by excessive heat, electricity, radioactivity, or corrosive chemicals that denature proteins in the skin cells.

First-degree burn

A burn that affects only the epidermis.

Second-degree burn

A burn that destroys the epidermis and part of the dermis.

Third-degree burn

A full-thickness burn that affects the epidermis, dermis, and subcutaneous layer.

Critical burns

Burns that cover a large percentage of the body or affect critical areas like the face, hands, feet, or perineum.

Rule of nines

A method used to estimate the surface area affected by a burn.

Haemostasis

The stoppage of bleeding to prevent blood loss.

Vascular spasm

Constriction of blood vessels to reduce blood loss.

Platelet plug formation

Platelets clump together to form a plug at the site of a broken blood vessel.

Blood clotting/coagulation

A series of reactions that transform blood from a liquid to a gel to form a clot.

Thrombus

A clot in an unbroken blood vessel that may block circulation and cause tissue death.

Embolus

A thrombus that breaks away and floats freely in the bloodstream, potentially clogging vessels in critical areas.

Bleeding disorders

Conditions like thrombocytopenia and haemophilia that affect the normal clotting process.

Haematoma

A collection of coagulated blood outside a blood vessel, often visible as bruises.

Phagocytosis

The process of engulfing and clearing cellular debris by phagocytes.

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