Basic Structure of the
Human Body
Cell
Cell Reproduction
Tissues
Introduction
 Human
body is an efficient, organized
machine
 Disease occurs when the machine does
not function correction
 Health care workers must understand
normal function of the body before
understanding the disease processes
Anatomy
 The
study of the form and structure of an
organism
Physiology
 Study
of the processes of living organisms
or why and how they work
Pathophysiology
 Study
of how disease occurs and
response of the body to disease process
Protoplasm
 Basic
substance of all life
 Material that makes up all living things
 Made of ordinary elements, such as
carbon, oxygen, hydrogen,sulfur, nitrogen
and phosphorus
 Scientist can combine these elements, but
they are not able to give it the
characteristics to produce life.
Cells

Basic unit of structure and function of all living
things; made of protoplasm
 Microscopic organisms that carry on all functions
of life
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Take in food and oxygen
Produce heat and energy
Move and adapt to their environment
Eliminate waste
Perform special functions
Reproduce to create new identical cells
Human body contains
trillions of cells.
Cells vary in shape and size
and perform many different
functions.
Basic parts of the cell
Cell membrane
 Outer
protective covering of cell
 Also called the plasma membrane or
plasmalemma
 Semipermeable allows certain substances
to enter and leave cell while preventing the
passage of other substance
Basic cell structure
Cytoplasm
 Semifluid
inside the cell membrane but
outside the nucleus
 Contains water (70 to 90 percent),
proteins, lipids, carbohydrates, minerals
and salts
 Site for all chemical reactions in cell
Basic Structure
Organelles
 Cell
structure that help a cell to function
 Located in cytoplasm
 Main organelles include the nucleus,
mitochondria, ribosome, lysosomes,
centrioles, golgi apparatus and
endoplasmis reticulum
Basic Structure
Nucleus
 Mass
in cytoplasm
 Separated from cytoplasm by a nuclear
membrane and contains pores to allow
substances to pass between the nucleus
 Often called the brains of the cell
 Controls many cell activities, including the
process of mitosis or reproduction
Basic Structure
Nucleolus
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One or more small round bodies located inside
the nucleus
Important in reproduction of the cell
Ribosomes made of ribonucleic acid (RNA) and
protein are manufactured in the nucleolus
Ribosomes move to cytoplasm to aid in
synthesis (production) of protein
Ribosomes can exist freely in the cytoplasm or
be attached to the endoplasmic reticulum
Basic Structure
Chromatin
 Located
inside the nucleus
 Made up of deoxyribonucleic aid (DNA)
and protein
 Chromatin condenses to from rod-like
structure called chromosomes during cell
reproduction
Chromosomes
 Human
cell has 46 chromosomes or 23
pairs
 Each chromosome contains between
30,000 and 45,000 genes, the structures
that carry inherited characteristics
 Each gene has a specific and unique
sequence of about 1000 base pairs of
DNA
Genes
 Each
gene has a specific and unique
sequence of about 1000 base pairs of
DNA
• DNA carries genetic coding that allows for exact
duplication of the cell
• DNA sequence on genes is unique for each
individual
• DNA is used as an identification tool similar to
fingerprints but much more exact
Genome

Total mass of genetic instruction humans inherit
from their parents
 Consists of strings of DNA nucleotides
 Human beings have about 3 billion nucleotides
in their genome
 Order of nucleotides on DNA sequences provide
instructions for body to build all of its parts,
everything from permanent structures such as
teeth and brain cells to short lived substances
such as blood and hormones
Basic Structure
Centrosome
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Located in cytoplasm near the nucleus
Contains two centrioles important in
reproduction
During mitosis, or cell division, the centrioles
separate
Thin cytoplasmic spindle fibers form between the
centrioles and attach to the chromosomes
Creates an even division of the chromosomes in
the two new cells.
Basic Structure
Mitochrondria

Rod-shaped organelles located throughout the
cytoplasm
 Called furnaces or powerhouses of the cell
 Break down carbohydrates, proteins and fats to
produce adenoside triphosphate (ATP) which is
major energy source of the cell
 Cell can contain just 1 to over 1000
mitochrondria depending on how much energy
the cell requires.
Cell Structure
Golgi Apparatus
 Stack
of membrane layers located in
cytoplasm
 Produces, stores, and packages
secretions for discharge from the cell
 Cells of salivary, gastric, and pancreatic
glands have large numbers of Golgi
appartus
Cell Structure
Endoplasmic reticulum


Fine network of tubular structures in cytoplasm
Allows for transport of materials into and out of
the nucleus
 Also aids in synthesis and storage of proteins
 Rough endoplasmic reticulum contains
ribosomes which are the sites for protein
synthesis
 Smooth endoplasmic reticulum does not contain
ribosomes and is not present in all cells; but it
does assist with cholesterol synthesis, fat
metabolism and detoxification of drugs
Cell Structure
Vacuoles
 Pouch
like structures found throughout
cytoplasm
 Have a vascuolar membrane with same
structure as cell membrane
 Filled with watery substances, stored food
or waste products
Cell Structure
Lysosomes
 Oval
or round bodies found throughout the
cytoplasm
 Contain digestive enzymes that digest and
destroy old cells, bacteria, and foreign
materials
 Fuse with stored food vacuoles to convert
food to a form that can be used by
mitochondria
Cell Structure
Pinocytic vesicles

Pocketlike folds in the cell membrane
 Allow large molecules such as protein and fat to
enter the cell
 When molecule is inside the cell, the pocket
closes to form a vacuole, or bubble, in the
cytoplasm
 When cell needs energy, vesicles fuse with
lysosomes to allow proteins and fats to be
digested and used by mitochondria to produce
ATP(energy).
Mitosis
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Asexual reproduction process used by most cell
Cells reproduce by dividing into two identical cells
Skin, blood forming, and intestinal tract cells reproduce
continuously
Muscle cells reproduce only every few years, but muscle
tissue can be enlarged with exercise.
Some specialized cells do not reproduce after birth
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Includes nerve cells in brain and spinal cord
If these cells are damaged or destroyed, others are not formed to
replace them
Process of mitosis
Meiosis
 Process
by which sex cells (gametes)
reproduce
 Process uses two separate cell divisions
to produce four new cells
 When female cells (ova) or male cells
(sperm) divide by meiosis, the number of
chromosomes is reduced to 23 or one half
the number found in cells created by
mitosis.
 When
oven and sperm join, zygote or new
cell, has 46 chromosomes or 23 pairs
 -- 23 chromosomes from ovum or
maternal cell
 23 chromosomes from sperm or paternal
cell
 Creates new individual with 23 pairs half
from mother and half from father.
Meiosis
Zygote begins period of rapid
mitotic division
 Within
four to five days, the zygote is a
hollow ball like mass of cells called a
blastocyst
 Within this blastocyst are embryonic stem
cells
 Stem cells have the ability to transform
themselves into any of the body’s
specialized cells and perform many
different functions.
Controversial area of research
 Scientists
attempting to determine whether
stem cells can be transplanted into the
body to cure diseases such as diabetes
mellitus, Parkinson’s, heart disease,
oseteoporosis, arthritis and spinal cord
injuries
Stem Cells
 Embryonic
cells
 Umbilical cord blood cells
 Adult tissues such as bone marrow and
liver (but these cells do not have the ability
to evolve into every kind of cell; these
stem cells evolve into more cells of their
own kind.)
Tissue

Cells of the same type join together for a
common purpose
 60 – 99 percent water with various substances
dissolved in it
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Fluid called tissue fluid
Slightly salty by nature
Dehydration: insufficient amount of tissue fluid
Edema: Excess amount of tissue fluid; swelling
Four groups of tissues
 Epithelial
tissue
 Connective tissue
 Nerve tissue
 Muscle tissue
Epithelial Tissue
 Covers
surface of body and main tissue in
skin
 Forms lining of intestinal, respiratory,
circulatory, and urinary tracts and other
body cavities
 Forms body glands where it specializes to
produce specific secretions for the body,
such as mucus and digestive juices
Connective Tissue
 Supporting
fabric of organs and other body
parts
 Soft connective tissue
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Adipose or fatty tissue: stores fat as reserve
food or source of energy, insulates the body,
fills the area between tissue fibers, and acts
as padding
Fibrous connective tissue: includes ligaments
and tendons that help hold body structures
together
Connective Tissue
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Hard connective tissue
- Cartilage: tough, elastic material found
between bones of spine and at end of long
bones where it acts as a shock absorber and
allows for flexibility; also found in nose, ears,
and larynx to provide form or shaping
- Bone: similar to cartilage but has calcium
salts, nerves, and blood vessels; frequently
called osseous tissue; helps form body structure
Connective Tissue
 Blood
and lymph (liquid connective tissue
or vascular tissue)
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Blood carries nutrients and oxygen to body
cells and metabolic wastes away from cells
Lymph transport tissue fluid, proteins, fats and
other materials from the tissues to the
circulatory system
Nerve Tissue
 Made
of special cells called neurons
 Controls and coordinates body activities
by transmitting messages throughout the
body
 Nerves, brain and spinal cord are
composed of nerve tissue.
Muscle Tissue
 Produces
power and movement through
contraction of muscle fibers
 Three main kinds:
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Skeletal: attaches to bones and provides
movement
Cardiac: causes the heart to beat
Visceral: located in walls of the respiratory,
digestive, urinary tract and blood vessels
Organs
 Two
or more tissues join together for a
specific function
 Examples include: heart, stomach, lungs,
and kidneys
Systems
 Organs
and other parts that join together
for a particular function
 Includes: integumentary, skeletal,
muscular, circulatory, lymphatic, nervous,
respiratory, digestive, urinary or excretory,
endocrine, and reproductive
Summary
 Protoplasm
is basic substance of life
 Protoplasm forms structural units called
cells
 Cells combine to form tissues
 Tissues combine to form organs
 Organs and other parts combine to form
systems
 Systems work together to create miracle of
human body.