Body Systems.txt

Bones of skull, vertebral column, ribs, sternum

Bones of upper and lower limbs

Cartilage and bone

Connective tissue composed of extracellular fibers in a matrix that contains cells in small cavities. Avascular.

Nourished by diffusion because there are no blood vessels, lymphatics or nerves.

Functions: support soft tissues, provide smooth gliding surface for bone articulation at joints, development and growth of long bones

Most common - moderate amount of collagen fibers.

Found in articular surfaces of bones (joints)

Matrix contains collagen fibers and a lot of elastic fibers (external ear, nose)

Matrix has low number of cells and in a large amount of collagen fibers (intervertebral discs)

Calcified, living connective tissue

Consists of intercellular calcified matrix with cells and collagen.

Function to: support body structures, protect organs, reservoirs of calcium and phosphorus, sites of muscle action for movement, containers for blood producing cells.

• -Long bones are tubular
• -Short bones are cuboidal
• -Flat bones have 2 compact bone plates separated by spongy bone
• -Irregular bones have various shapes
• -Sesamoid bones are round and develop in tendons

Few nerve fibers, only vasomotor fibers that regulate blood flow

Dense bone that forms outer shell of all bones and surrounds spongy bone

Trabecular or Cancellous bone. Spicules of bone enclosing cavities containing marrow.

All bones covered in this fibrous connective tissue membrane except for areas of joints containing hyaline cartilage

• -Can form new bone
• -receives blood vessels that supply compact bone
• -many nerve fibers, sensitive to injury

-Occur where bones involved are separated by an articular cavity

• -A layer of hyaline cartilage covers articular surfaces of joints with the cavity in between the cartilage.
• -Enclosing the cavity is a Joint Capsule made of the inner Synovial Membrane and the Fibrous Membrane

• -Attaches to the joint surfaces where the cartilage and bone connect to enclose the articular cavity.
• -highly vascular and produces synovial fluid, which seeps into the cavity and lubes the articular surfaces
• -Can occur outside of joints in the form of synovial bursae or tendon sheaths, which also help to reduce friction.

• -Dense connective tissue that surrounds and stabilizes the joint
• -Can thicken to form ligaments to further stabilize the joint

Bones that are connected to each other by either fibrous tissue or cartilage.

Fibrous Joints-Sutures, Gomphoses, Syndesmoses

Cartilaginous Joints- Synchondroses, symphyses

Solid, fibrous joints in the skull, bones connected together by a Sutural Ligament

Fibrous joints that occur between the teeth and the adjacent bone

-short, collagen tissue fibers in the periodontal ligament run between tooth and bone

Fibrous Joints where two adjacent bones are linked by a ligament, such as the ligamentum flavum connecting vertebral laminae.

Ex. Interosseous Membrane, links the radius and the ulna together

Cartilaginous joint (solid joint) that happens where two ossification centers in a developing bone remain separated by a layer of cartilage, such as in the growth plate between head and shaft of developing long bones.

Allow bone growth to occur, and eventually gets calcified over

Solid, cartilaginous joints where two bones are separated by a layer of cartilage - most occur in the midline such as the pubic symphysis between two pelvic bones

Ex. 2: Invertebral discs between two vertebrae

-Epidermis: outter cellular layer of stratified squamous epithelium (avascular)

-Dermis: Dense bed of vascular connective tissue

• Functions as a mechanical and permeability barrier, sensory and thermoregulatory organ
• -can initiate primary immune responses

Connective tissue containing varying amounts of fat that separate, support, and interconnect organs and structures, enable movement of one structure relative to another, and allow the transit of vessels and nerves from one area to another.

• Two categories:
• 1. Superficial (subcutaneous) Fascia
• 2. Deep Fascia

• -Also called subcutaneous tissue
• -Just deep to and is attached to the dermis
• -Loose connective tissue with lots of fat
• -Thickness varies around body and among different people
• -Allows movement of skin over deeper areas of the body, acts as a conduit for vessels and nerves to and from skin, and serves as a fat reservoir

• -Dense, organized connective tissue
• -Outer layer of deep fascia is attached to the deep surface of the superficial fascia and forms a thin fibrous covering over most of the deeper region of the body
• -Inward extensions of the outer layer compartmentalize muscles with similar function/innervation.
• -Can surround individual muscles and vessels
• -Can thicken near joints (retinacula)

• -Layer of deep fascia separating the parietal peritoneum (membrane lining abdominal cavity) from the fascia covering the deep surface of the muscles of the abdominal wall (transversalis fascia)
• -Similar layer in the thorax is called Endothoracic Fascia

• -Parallel bundles of long, multinucleated fibers with transverse stripes, capable of contraction
• -Innervated by somatic and branchial motor nerves
• -Moves bones and other structures, gives form and support to the body
• -Named on the basis of shape, attachments, function, position, or fiber orientation

• -Striated muscle only found in the walls of the heart (myocardium) and in some of the vessels large vessels that join the heart
• -Branching network of individual cells linked electrically and mechanically
• -less powerful contractions
• -Resistant to fatigue
• -Innervated by visceral motor nerves

• -Not striated, consists of elongated or spindle-shaped fibers capable of slow and sustained contractions
• -Found in walls of blood vessels (tunica media)
• -Associated with hair follicles in the skin
• -Found in the eyeball, walls of gastrointestinal, respiratory, genitourinary, and urogenital systems.
• -Innervated by visceral motor nerves

• -Heart and blood vessels
• -Arteries: transport blood away from the heart
• -Veins: Transport blood toward the heart
• -Capillaries: connect arteries and veins, smallest blood vessels, where oxygen, nutrients and wastes are exchanged in tissues

• -Tunica Externa: outer connective tissue layer
• -Tunica Media: middle smooth muscle layer
• -Tunica Intima: inner endothelial lining of vessels

1. Large elastic arteries: contain lots of elastic fibers in tunica media, allowing expansion and recoil during cardiac cycle.  Helps maintain blood flow during diastole.  (ex. Aorta, brachiocephalic trunk, left common carotid artery, etc...)

2. Medium muscular arteries: their tunica media contains mostly smooth muscle fibers.  Allows them to regulate diameter and blood flow to different parts of the body (ex. femoral, axillary, radial)

3. Small arteries/arterioles: control filling of capillaries and directly contribute to arterial pressure

1. Large Veins: some smooth muscle in tunica media, but thickest layer is tunica externa (ex. superior vena cava, inf. vena cava, portal vein)

2. Small/medium veins contain small amounts of smooth muscle and thickest layer is tunica externa (ex. superficial veins in upper and lower limbs and deeper veins of leg and forearm)

3. Venules are smallest and drain capillaries

• -Walls of tunica media are thinner
• -luminal diameters of veins are large
• -Often multiple veins associated closely with arteries in peripheral regions
• -Valves are present in veins, in peripheral vessels inferior to the level of the heart.  (Paired cusps that facilitate blood flow toward heart)

• -Begin as porous capillaries in tissues and converge into larger vessels that connect to veins in the neck
• -Mainly collect lost fluid from vascular capillary beds during nutrient exchange and deliver back to the veins of the vascular system.
• -Pathogens also drain into lymph, cells of lymphocytic system, hormones, and cell debris
• -Fats absorbed by the small intestine are packaged into chylomicrons (lipid droplets), are released from cells and enter the lymphatic capillaries (lacteals in small intestine)
• -Lymph is clear fluid that travels in the lymphatic vessels.  If originating from the small intestine, the that lymph is milky and opaque because of chylomicrons and is called chyme.
• -Lymphatic vessels exist everywhere except brain, bone marrow, and avascular tissues
• -Lymph movement generated by skeletal muscle movement and arterial pulses.  Unidirectional flow maintained by valves

• -Small, encapsulated structures that interrupt lymphatic vessel flow
• -Contains immune defense cells (lymphocytes and macrophages)
• -Filter and phagocytose particulate matter in lymph
• -Detect and defend against foreign antigens
• -Flow through lymph nodes is slow, many metastases are carried to lymph nodes and lodge there creating secondary tumors
• -If a lymph node is draining infected or diseased regions, lymph node can become enlarged or hard/tender
• -Clusters of lymph nodes appear where there is high risk of pathogen- body's surface, digestive system, and respiratory system.
• -Also abundant and palpable in axilla, groin, and femoral region

• -All lymphatic vessels converge to form large trunks or ducts that drain into venous system where internal jugular veins join the subclavian veins to form the brachiocephalic veins.
• -Lymph from the right side of the head and neck, right upper limb, right side of thorax, and right side of the upper and more superficial region of abdominal wall is carried by lymphatic vessels that connect with veins on the right side of the neck.
• -Lymph from all other regions drain into veins on the left side of the neck

• Structural: CNS (Brain + Spinal cord) and PNS (all nervous structures outside CNS, such as spinal and cranial nerves, visceral nerves and plexuses, and the enteric system)
• Functional: Somatic and Visceral

• 1. Cerebral Hemispheres compsed of:
•     -Gray Matter - Outter layer, cell bodies
•     -White Matter - Inner layer, axons forming tracts
•     -Ventricles - spaces filled with cerebrospinal fluid

2. Cerebellum - two lateral lobes and a midline

3. Brainstem - composed of diencephalon, midbrain, pons, and medulla

Part of CNS in the superior 2/3rds of vertebral canal.

Three layers of connective tissue that cover, protect, and suspend the brain and spinal cord within their cavities.

• -Dura Mater: thickest and most external
• -Arachnoid Mater: lies against internal surface of dura mater
• -Pia Mater: adherent to brain and spinal cord

-Between the aracnoid and pia mater is the subarachnoid space containing the cerebrospinal fluid

• -Composed of nerves that carry conscious sensations from periphery back to CNS, and nerves that innervate voluntary muscles
• -involved in receiving and responding to information from external environment

• -Innervates organ systems in the body and other visceral elements such as smooth muscle and glands in the periphery.
• -Responds to information from the internal environment