Human Anatomy Vocab Quiz 3 (27-44)

Connective Tissue

Most abundant, widely distributed tissue; few cells in lots of extracellular matrix

• Functions: binding and support, protection, insulation, transport of substances

1. Loose – adipose

2. Dense – tendons and ligaments

3. Supporting – bone and cartilage

4. Fluid – blood.

Collagen Fibers

Fibers in the matrix that provide strength

• One of 3 fiber types in the extracellular matrix (collagen = strength, elastic = stretch, reticular = fine network).

• Collagen is the main fiber in dense connective tissue, forms a network in hyaline cartilage, thick fibers in fibrocartilage, and many are found in bone matrix

• Made by fibroblasts.

Bone

Osseous tissue: hard, calcified matrix with blood vessels

• Supporting connective tissue.

• Functions: support and protect (by enclosing), stores calcium/minerals/fat, marrow is the site of blood cell formation (hematopoiesis).

• Cells: osteoblasts, osteocytes (lie in lacunae).

• Location: bones.

Osteocytes

Mature bone cells that lie in lacunae

• Osteocytes lie in small spaces called lacunae, arranged in rings between the lamellae around the central (Haversian) canal.

Osteon

Haversian system: the structural unit of compact bone

• Osteon is a central (Haversian) canal, which carries blood vessels, surrounded by concentric rings of matrix called lamellae.

• Osteocytes sit in lacunae between the lamellae

Cartilage

Flexible supporting tissue with no nerves or blood

• Functions: support, resists compression.

• Cells: chondroblasts (produce the matrix) and chondrocytes (mature cells that lie in lacunae).

• Locations: larynx, joints, tip of nose, ear, intervertebral discs, rib-breastbone, knee joint.

• Subclasses: hyaline, elastic, fibrocartilage.

Hyaline Cartilage

Amorphous but firm matrix; collagen fibers form an imperceptible network

• Function: supports and reinforces, has resilient cushioning properties, resists compressive stress.

• Locations: forms most of the embryonic skeleton; covers ends of long bones in joint cavities; costal cartilages of the ribs; cartilages of the nose, trachea, and larynx.

Elastic Cartilage

Similar to hyaline cartilage, but with more elastic fibers in the matrix

• Function: maintains the shape of a structure while allowing great flexibility.

• Location: supports the external ear (pinna); epiglottis.

Fibrocartilage

Matrix similar to but less firm than hyaline; thick collagen fibers predominate

• Function: tensile strength with the ability to absorb compressive shock.

• Locations: intervertebral discs, pubic symphysis, discs of the knee joint.

Dense Connective Tissue

Connective tissue made mainly of collagen fibers that resists tension

• Subclass: dense regular (tendons and ligaments).

• Structure: primarily parallel collagen fibers, a few elastic fibers.

• Functions: elastic, resists tension, withstands great tensile stress when pulling force is applied in one direction.

• Cell: fibroblasts.

• Locations: tendons (muscle-bone), ligaments (bone), aponeuroses, lower layers of skin.

Tendons

Dense regular connective tissue attaching muscle to bone

• Type of dense regular connective tissue.

• Mainly parallel collagen fibers with fibroblasts in between.

• Attach muscles to bones (or to muscles) and withstand great tensile stress when pulling force is applied in one direction.

Ligaments

Dense regular connective tissue attaching bone to bone

• Type of dense regular connective tissue (most ligaments).

• Mainly collagen fibers, with fibroblasts as the major cell.

• Resist tension and hold bones together at joints, for example the shoulder joint.

Loose Connective Tissue

'Universal packing material': softer, fewer fibers, gel-like matrix

• Subclasses: areolar, adipose, reticular.

• Functions: cushion and protect organs (areolar, fat), store nutrients (fat), internal framework (reticular), fight infection (areolar).

• Cells: fibroblasts, adipocytes.

• Locations: under skin, lymph nodes, hips, behind eyeballs.

Adipose Tissue

Loose connective tissue of closely packed fat cells (adipocytes)

• Adipocytes have the nucleus pushed to the side by a large fat droplet (vacuole).

• Function: provides reserve food fuel; insulates against heat loss; supports and protects organs.

• Locations: under skin in the hypodermis; around kidneys and eyeballs; within abdomen; in breasts.

Blood

Fluid connective tissue within blood vessels with no fibers

• Subclasses: blood cells and plasma.

• Red and white blood cells in a fluid matrix (plasma).

• Function: transports respiratory gases, nutrients, wastes, hormones, and other substances.

• Cells: white blood cells (leukocytes), red blood cells (erythrocytes), platelets.

• Location: contained within blood vessels.

Erythrocytes

Red blood cells

• They are the most numerous cells in a blood smear and surround the white blood cells.

• Function: transport respiratory gases, they carry oxygen using hemoglobin

Leukocytes

White blood cells

• Five types: neutrophil, eosinophil, basophil, lymphocyte, monocyte.

• In the blood smear, a neutrophil and a lymphocyte are surrounded by red blood cells.

• They defend the body against infection.

Plasma

The fluid matrix of blood in which cells are suspended

• A subclass of blood (blood cells + plasma).

• Blood is a fluid matrix with no fibers.

• Transports nutrients, wastes, gases, and hormones.