Introduction to

Human Anatomy

Some definitions Morphology -form that structures take on. -Morphology affects function Structure -a part of the body. Can either be microscopic (small)

or macroscopic (large). Function -refers to physical behavior. What a structure does. -Function is related to structures=Functional

Morphology

Normal vs. Abnormal -We must understand the normal

situation to be able to compare it with and recognize the abnormal.

Topographic Anatomy -Structures on the surface of the skin

can be used to identify and locate deeper structures, organs, and tissues beneath the skin.

Structure defines and restricts function.

- certain joints can only move in one direction. For example a hinge joint can only have motion perpendicular to the axis of the joint. The knee joint (hinge) cannot have motion in the lateral direction because that goes against the axis.

ANATOMY

Study of structure.

ANA = apart

TOMY = to cut

Anatomy

GROSS HISTOLOGY

Structures can only be seen with a microscope

Structures can be seen withthe naked eye.

Surface Anatomy

Study of shapes and landmarkson the surface of the body

Cells and cell parts

Dissection

Systemic

Regional

All structures of a region are studied together

All structures with related functions are studied together

Our study of Human Anatomy will look at both, gross and histological anatomy.

Anatomical Terminology

Anatomical Axes - axes are like skewers which pass through the body. They are used to describe axes about which rotation movements take place - very similar to the pin in a door hinge. The door moves in a plane around an axis - the plane is determined by the orientation of the pin in the hinge.

Superior

Inferior

Anatomical Position

This is a reference position that allows for the use of consistent directional terminology.

All descriptions of location are made from within anatomical position.

Subject is facing forward with palms forward, thumbs facing to the sides.

Anatomical Position

This is the position from which all directions and descriptions are made.

The person is standing erect, palms facing anteriorly, feet together and facing forward.

Superior

Inferior

TRANSVERSE PLANE

TRANSVERSE PLANE

Body Midline

Medial

Lateral

EYES

EARS

Sagittal

Plane

The Extremities have a different set of terms

The upper arm is

PROXIMAL

The arm is

DISTALTO THE TRUNK or MIDLINE OF THE BODY

The eyes are SUPERIOR to the mouth.

The mouth is INFERIOR to the eyes.

The umbilicus is ANTERIOR to the gluteus maximus.

IN FRONT OF

The gluteus maximus is POSTERIOR to the umbilicus.

IN BACK OF

BACK FRONT

Also called VENTRAL

Also called DORSAL

CORONAL

P

L

A

N

E

In four legged animals, the head is ANTERIOR to the tail. In two legged animals, the head is SUPERIOR to the tail.

In four legged animals, the region toward the head is CRANIAL. The region toward the tail is CAUDAL.

TEST YOUR KNOWLEDGE

What is the relationship?

knee to thigh

Nipple to belly button

Chin to eyes

Little toe to big toe

SKIN

SUPERFICIAL – toward the surface

DEEP – away from the surface

ORIGIN – attachment of muscle on a fixed point, closest to midline

INSERTION – attachment of muscle that is moveable, farthest from midline.

THIGH BONE (FEMUR) L

EG BONE

DIRECTIONAL TERMS FOR MUSCLES

Medial vs. Median

A median structure is one which is in the median (midline) plane of the body

(such as the sternum, the umbilicus and the symphysis pubis).

The term medial is a relative term and must be used to compare two

structures; one structure being medial or closer to the median plane of the

body than the other structure.

Hands and Feet:

Palmar or Volar means the anterior surface or palm of the

hand.

Plantar means the inferior surface or sole of the foot.

Dorsum of the hand and foot

refers to the superior surface of the foot and posterior surface of

the hand.

Ipsilateral and Contralateral refer to the same or opposite sides of the

body, respectively.

Ipsilateral refers to the same side of the body, e.g., the right arm and right leg are ipsilateral

structures.

Contralateral refers to opposite sides of the body;

e.g., the right arm and the left arm are contralateral structures.

Cardinal Body Planes

Cardinal Body Planes

Regional Terminology

Organization of the Human Body

The body is organized from the smallest part to the largest part.

Chemical Level - atoms, molecules - carbohydrates, lipids, fats, proteins, nucleic acids Cellular Level -simplest structural unit -basic unit of life -smallest unit that can live on its own

Tissue Level

- a group of cells with common origin, structure, and function.

- cells within a tissue all work toward a common goal (i.e.: movement, nutrition, etc.)

Organ Level

- a group of tissues that have a common function.

Organ System Level

- a group of organs with a special function.

- Digestive System, Nervous System, etc… Organismal Level

- A group of organ systems that at some point in time is capable of sustaining life.

- All organ systems work together in an organism.

Human Body Plan

Vertebrates Have Some Common Features

1. Tube within a tube body plan

inner tube – mouth to anus

- respiratory organs

- digestive organs

outer tube – axial skeleton

- axial musulature

2. Bilateral Symmetry

- left half of the body is a mirror image of the right half.

- structures in the median plane are unpaired, but have identical left and right sides.

3. Dorsal hollow nerve cord

- develops into the brain and spinal cord.

4. Notochord

- stiff rod just deep to the spinal cord.

- present in the embryo, but is replaced by

the vertebrae later in development.

5. Segmentation

- repeating units of similar structures running along the length of the trunk.

- examples include the ribs and intercostal muscles and the vertebral column.

6. Pharyngeal Pouches

- pharynx – outpouchings called pouches that correspond to the clefts between the gills of a fish.

- present in the embryo only.

Body Cavities and Membranes Dorsal Body Cavity - cranial cavity - vertebral cavity Ventral Body Cavity - contains the viscera - 2 divisions 1. thoracic cavity a. Pleural cavity b. Mediastinum c. Pericardium 2. abdominal cavity a. Abdomen b. Pelvis Serous Cavities - 2 layers parietal layer - outer walls of the cavity visceral layer – inner layer covers the visceral

organs water between the membranes is a watery

fluid

The abdomen is divided into four quadrants which are further subdivided into nine regions.

Each region is named for its relationship with the umbilicus.

Clinically, each region is associated with specific organs.

Fertilization: Four Major Steps

1. Sperm contacts the egg

2. Sperm or its nucleus enters the egg

3. Egg becomes activated and developmentalchanges begin

4. Sperm and egg nuclei fuse

Words to know… Fuse- to physically join together Ovum – egg cell (female gamete) Cleavage – process of cell division during

development Differentiation – the process of forming different

kinds of cells from similar cells of the early embryo Embryo – an organism in an early stage of

development Morula – solid ball of cells formed from cleavage Blastula – hollow ball of cells formed from cleavage Gastrula – a hollow ball of cells with an “in pushing”

and 3 layers (germ layers)

Fertilization

The Nuclei Fuse Together

Development of the zygote, the study of which is known as embryology or developmental biology.

The zygote undergoes a series of mitotic cell divisions called cleavage.

The stages of development are: Fertilized ovum (zygote) 2-cell stage 4-cell stage 8-cell stage Morula Blastula Early Gastrula Late Gastrula

Cleavage (divide via mitosis) forms the 2 cell stage

And eventually form a Morula

And next, a gastrula

The Regents Diagram…

Sperm and ovum

1. Zygote (fertilized ovum)

2. 2-cell stage

3. 4-cell stage

4. Morula

5. Blastula

6. Gastrula

Differentiation (Organogenesis) Organogenesis is the formation of the organs (Organo =

organs, genesis = creation) Arises from the layering of cells that occurs during

gastrula stage The layers are germ layers; they have specific fates in

the developing embryo: – Endoderm

• The innermost layer• Goes on to form the gut

– Mesoderm• In the middle• Goes on to form the muscles, circulatory system, blood and

many different organs– Ectoderm

• The outermost• Goes on to form the skin and nervous system

Late Gastrula

Mesoderm

Endoderm

Ectoderm

Differentiation of Primary Germ Layers (from the gastrula)

Ectoderm Mesoderm Endoderm

Nervous system

Skeleton Digestive tract

Epidermis of skin

Muscles Respiratory system

Circulatory system

Liver, pancreas

Gonads Bladder

Early Human Development Summary

Meiosis makes sperm in males and ovum in females

Sperm and ovum unite nuclei to form a zygote

Zygote undergoes cleavage and becomes gastrula with 3 germ layers