Introduction to Human Anatomy

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Introduction to Human Anatomy
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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 structuresFunctional
  Morphology

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• 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.

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• 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.

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ANATOMY

• Study of structure.
• ANA apart
• TOMY to
  cut

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Our study of Human Anatomy will look at both,
gross and histological anatomy.
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Anatomical Terminology
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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.
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Superior
Inferior
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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.

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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.
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Superior
TRANSVERSE PLANE
Inferior
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Body Midline
EYES
Medial
Sagittal Plane
Lateral
EARS
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The Extremities have a different set of terms
The arm is DISTAL
TO THE TRUNK or MIDLINE OF THE BODY
The upper arm is PROXIMAL
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The eyes are SUPERIOR to the mouth.
The mouth is INFERIOR to the eyes.
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BACK
FRONT
CORONAL P L A N E
The umbilicus is ANTERIOR to the gluteus maximus.
The gluteus maximus is POSTERIOR to the umbilicus.
IN FRONT OF
IN BACK OF
Also called VENTRAL
Also called DORSAL
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• 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.

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TEST YOUR KNOWLEDGE

• What is the relationship?
• knee to thigh
• Nipple to belly button
• Chin to eyes
• Little toe to big toe

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SKIN
SUPERFICIAL toward the surface
DEEP away from the surface
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DIRECTIONAL TERMS FOR MUSCLES
ORIGIN attachment of muscle on a fixed point,
closest to midline
INSERTION attachment of muscle that is
moveable, farthest from midline.
THIGH BONE (FEMUR)
LEG BONE
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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.
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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.
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Ipsilateral and Contralateral refer to the same
or opposite sides of the body, respectively. Ips
ilateral 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.
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Cardinal Body Planes
Cardinal Body Planes
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Regional Terminology
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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

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• 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.

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• 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.

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Human Body Plan

• Vertebrates Have Some Common Features
• Tube within a tube body plan
• inner tube mouth to anus
• - respiratory organs
• - digestive organs
• outer tube axial skeleton
• - axial musulature

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• 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.

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• Dorsal hollow nerve cord
• - develops into the brain and spinal
  cord.
• Notochord
• - stiff rod just deep to the spinal
  cord.
• - present in the embryo, but is
  replaced by
• the vertebrae later in development.

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• Segmentation
• - repeating units of similar structures
  running along the length of the trunk.
• - examples include the ribs and intercostal
  muscles and the vertebral column.

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• Pharyngeal Pouches
• - pharynx outpouchings called pouches that
  correspond to the clefts between the gills of a
  fish.
• - present in the embryo only.

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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

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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.
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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

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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)

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Fertilization
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The Nuclei Fuse Together
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• 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

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Cleavage (divide via mitosis) forms the 2 cell
stage
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And eventually form a Morula
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And next, a gastrula
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The Regents Diagram

• Sperm and ovum
• Zygote (fertilized ovum)
• 2-cell stage
• 4-cell stage
• Morula
• Blastula
• Gastrula

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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

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Late Gastrula
Endoderm
Ectoderm
Mesoderm
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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
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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