SPHS 170

Introduction

Definitions

ANATOMY- Greek: to cut up the structure.

PHYSIOLOGY- Greek: physis= nature, logis= logic. A branch of biology that deal with the processes and activities of living beings and relates form to function.

Anatomical Nomenclature

Between the time of Vesalius and the end of the nineteenth century, anatomical names proliferated so that approximately 5,000 structures had 50,000 names.

In 1895 an international meeting was held in Basel, Switzerland for the purpose of

adopting a universal anatomical nomenclature.

It was known as the BNA

Basel Nomina Anatomica

Follows these principles:

1. All terms are in Latin but, countries can

translate for teaching purposes.

2. Each structure has one term.

3. Terms should be descriptive.

Anatomical Position and Planes1. The anatomical position

The anatomical position is used for direction and orientation. The basic position is upright with the palms forward and the thumbs extended peripherally.

2. Planes a. Sagittal - any vertical plane.

b. Frontal or coronal - section dividing front and

back.

c. Transverse or Horizontal - a section alon

any horizontal plane.

Directions and Positionsa. Ventral - away from the backbone-toward the front

of the body.

b. Dorsal - toward the backbone or away from the front of the body.

c. Anterior - toward the front, away from the back.

d. Posterior - toward the back, away from the front.

e. Medial - toward the axis or midline.

f. Lateral - away from the axis or midline.

g. Proximal - toward the body or toward the root.

h. Distal - away from the body.

Directions and Positions

i. Cranial or rostral - toward the head.

j. Caudal - toward the tail.

k. External - toward the outer surface.

l. Internal - toward the inner surface.

m.Superficial - toward the surface.

n. Superior- upper, distinct from

superficial.

o. Inferior lower as distinct from deep.

ELEMENTARY TISSUES (PLATE 511)

There are five basic tissue types:

epithelial

connective

muscular

nervous

vascular

Tissue Derivation

At the stage when the embryo is a blastoderm, some of the cells become detached and migrate into the cavity of the vesicle.

The inner layer is known as the endoderm (gr ento, inside + derma, skin).

The outer layer is the ectoderm.

Tissue Derivation

Cells then fill the space between the endo and ectodermal layers.

The embryo has become trilaminar and the intermediate layer is the mesoderm.

These three layers are known as the germ layers of the embryo

1. EPITHELIAL TISSUE TYPES

Epithelial cells are characteristically arranged in mosaics, forming sheets of tissue that cover the surfaces of the body, line tubes, or passages leading to the interior of the body and almost without exception line the cavities of the body.

There are three types of epithelium.

Epithelium Proper

Forms the epidermis (outer layer of the skin) and the internal membranes which are continuous with the skin (mucous membranes lining the digestive, respiratory, urinary, and generative tracts.)

The shape of the cells is varied. OVERHEAD

Endothelial tissue

is confined almost exclusively to the inner lining of the blood and lymph vessels, and unlike internal epithelial tissue has no continuity with the epidermis.

Endothelial tissue is composed of extremely flat, single layers of cells which creates a very smooth surface.It creates the lining of the blood vessels.

Mesothelial tissue

a specialized form of epithelial tissue, which lines:

the primary body cavities;

the two pleural cavities,

the peritoneal cavity,

and the pericardial cavity.

2. CONNECTIVE TISSUE

Connective tissue has relatively few cells and a proportionately large amount of intercellular substance. These noncelluar components are called matrix.

Connective tissue is classified on the basis of the characteristics of the nonliving intercellular substances which compose the matrix and not on the living cell characteristics.

A. Loose Connective Tissue

binds parts together but allows plenty of movement

1. Areolar tissue - a very loose tissue in which the cells lie in an irregular network of fibers. Commonly found just beneath the skin forming the bed for the skin and mucous membrane.

2. Adipose tissue - very similar to areolar but with many fat cells.

B. Dense Connective Tissue

characterized by an abundance of of closely packed fibers.

Collagenous fibers predominate in many dense connective tissues. > gelatin.

Other dense connective tissues are characterized by the predominance of Elastic fibers.

DCF are classified on the basis of intercellular substances. White and unyielding or yellow and elastic.

Tendons

Tendons are tough nonelastic cords composed of closely packed parallel fibers.

Tendons attach muscles to bone, cartilage or sometimes to one another.

White, flattened, tendonous coverings of muscles are called aponeuroses. (PLATE 61)

Ligaments

Ligaments are also characterized by closely packed parallel fibers.

HOWEVER, they have many elastic fibers.

They join bone to bone, cartilage to bone and cartilage to cartilage.

FasciaFascia is characterized by irregularly arranged

fibers.

Commonly associated with muscles are are responsible for the arrangement of muscles into functional mechanical mediators of movement.

Subcutaneous fascia (tela subcutanea) is found over the entire body just under the skin.

Keeps us from falling apart

Reticular Tissue

Reticular tissue is a very delicate matrix of cells which have processes extending in all directions to join neighboring cells.

It is a primitive tissue that often provides supporting framework for essential organs like the liver.

SKELETAL SYSTEM: Cartilege

Cartilage - is composed of cells, ground substance and intercellular spaces.

Chondroblasts - the cells of cartilage

Lacunae - irregularly shaped spaces in the ground substance in which chondroblasts are found.

In early stage of development, cartilage forms the entire skeleton. Cartilage is capable of growth. Growth is via proliferation of chrondroblasts.

Skeletal Sysytem: Cartilege

All cartilage is covered by a though fibrous covering called the perichondrium. Union between muscles and tendons is made possible by the perichondrium.

There are three cartilage sub-types classified by the nature and relative concentrations of fibrous substances:

Hyaline Cartilage

Hyaline Cartilage. Appears bluish-white, & transparent when fresh.

It covers the articular surfaces of the joints and forms the framework for the lower respiratory

tract.

Hyaline Cartilage has no blood supply. With age it becomes yellow and brittle and may ossify.

Elastic Cartilage

Elastic Cartilage Appears somewhat yellow and opaque because of the many elastic fibers in its matrix.

It is flexible, almost rubbery. Found in the external ear, external auditory meatus, epiglottis and some bits in the larynx.

Calcification of this type of cartilage rarely occurs.

Fibrocartilage

Fibrocartilage. Characterized by a dense network of collagenous fibers and cartilage cells. Forms the intervertebral discs of the vertebral column.

Skeletal System: Bone

Bone (osteum) is the other specialized dense connective tissue.

It is characterized by a rigid matrix (intercelluar substance).

Bone is composed of osteoblasts and osteocytes, collagenous fibers and ground substance.

Rigidity of bone is due to the large amounts of inorganic salts that are deposited in its matrix.

Skeletal System: Bone

The salts make up about two-thirds of the weight of the bone. Salts are composed of:

85% calcium phosphate

10% calcium carbonate

calcium flouride

magnesium floride

Skeletal System: Bone

Bone withstands compression as well as concrete and is very tensile.

There are 206 bones in the adult human skeleton.

The skeleton is divided into the axial and appendicular skeletons.

Skeletal System: Bone

Periosteum covers all bone marrow except at the articular surfaces.

Periosteum performs two functions:a. provides attachment for muscle tendons.

B. contains osteoblasts which assist in the initial formation of new bone and later in life generate new bone for repair

Two types of bone can be identifieda. compact bone forms the hard outer coveringb. spongy bone forms the inner core

Skeletal Terms

Elevations Depressionscondyle fissurecrest foramenhead fossaprocess foveaspine groovetuberosity meatus

necksinussulcus

Classifications of JointsThree major categories:1. Synarthrodial-the bones are in almost direct

contact and joined together by thin connective tissue so as to prevent movement (cranium).

2. Amphiarthrodial-cartilaginous, yielding (two types)

a.synchondros is rather rigid joint that ossifies with

age, such as the skull at birth.B.symphysis edges of bone are connected by fibrocartilage, articular facets are covered by hyaline cartilage with fibrocartilage between. Ex. vertebra, two pubic bones

Classifications of JointsDiarthrodial joints (movable)-bones are

joined by a band of fibrous tissue called the articular capsule, within which is the joint capsule.

A small amount of fluid is produced within the cavity to lubricate the joint.

There are six types of diarthrodial joints and the are classified on the basis of their movements

3. MUSCLE TISSUE

There are 329 muscles in the body all but 2 are paired; diaphragm, procerus.

Muscle accounts for about 40% of total body weight.

It is composed of 2 proteins; myosin and actin.

Muscles usually have two attachments:Origin refers to the attachment that is fixed or less engaged in movement.Insertion is associated with the structure being acted upon -in extremities the more distal attachment

Muscle Tissue: Three TypesA. Striated muscle is also known as skeletal

muscle. It consists of long fibers crossed at regular intervals by transverse bands.

B. Smooth muscle is more primitive than striated. Innervated by the autonomic nervous system, thus independent of direct voluntary control. Found in blood vessels, digestive system, bronchial tubes.

C. Myocardium is found only in the heart and properties of both smooth and striated muscle

4. NERVE TISSUE

Nerve tissue is composed of extremely long, irritable cells that are able to modify their biochemical composition.

The basic parts of a nerve are 1. Cell body 2. Dendrites-these processes carry information to

the cell body from other cells. Dendrites tend to be short with multiple branches

3. Axons-conduct information away from the cell body to other cells. Axons range in length from much less than a millimeter to a meter

5. Nerve TissueNerves are bundles of nerve cells, their axons

and dendritess.

Sensory nerves are almost exclusively afferent -conduct toward from the cell body.

Motor nerves are almost exclusively efferent-conduct information away from the cell body.

Mixed nerves have afferent and efferent components.

The Synapse

Neural synapses permit information to travel in just one direction.

Neural tissue is capable of manufacturing the chemical agents (neurotransmitters)that inhibit or facilitate neural transmission.

There are about 50 neurotransmitters

The SynapseThe initial neural impulse is an electrochemical wave

that is propagated much like a trail of burning gunpowder. (overhead)

Note the discontinuity in the trail between the neurons. This represents the synaptic cleft between the two neurons.

As the impulse reaches it’s termination, the small mound at the end (terminal bouton) releases another bolus of neurotransmitter which causes a change in the chemical composition of the nearby neural ending.

However, the neural ending are never in direct contact with one another.

Motor UnitThe motor unit is a functional unit for producing

movement.It consists of a nerve cell and all the muscle

fibers innervated by that nerve cell.Some muscles have a high innervation ratio-

there are many muscle fibers innervated by a few nerves. These muscles produce crude, large movements.

Muscles with a low innervation ratio, a few muscle fibers have lots of neural innervation. These muscles are capable of small refined rapid movements.

5. Vascular Tissue

Comprises @ 10% of total body weight. Blood is composed of corpuscles and

platelets in plasma. Erythrocytes have no nuclei and so are not

true cells. Nuclei are present early in development and then disappear.

Lymph is the nutrient plasma of the tissues and the cells in lymph are called lymphocytes.