Download حسام العزاوي .د LEC.2 Body Organization All organisms are built from

LEC.2
‫حسام العزاوي‬. ‫د‬
Body Organization
All organisms are built from simple to more complex levels Chemicals
form the materials that make up cells, which are the body’s structural and
functional units. Groups of cells working together make up tissues, which
in turn make up the organs, which have specialized functions. Organs
become components of the various systems, which together comprise the
whole organism.
The Cell
The cell is the basic unit of living organisms. Cells accomplish all the
activities and produce all the components of the body. They carry out
metabolism, the sum of all the body’s physical and chemical activities.
They provide the energy for metabolic reactions in the form of the
chemical ATP (adenosine triphosphate), commonly described asthe
energy compound of the cell. The study of cells is cytology (sī-TOL-ōjē), based on the root cyt/o, meaning “cell.” has career information
in the fi eld of cytology.
Levels of organization. The organ shown is the stomach,
which is part of the digestive system.
Tissues
Cells are organized into four basic types of tissues that perform
specifi c functions:
■ Epithelial (ep-i-THĒ-lē-al) tissue covers and protects body structures
and lines organs, vessels, and cavities
■ Connective tissue supports and binds body structures
■ Muscle tissue (root: my/o) contracts to produce movement. There are
three types of muscle tissue:
■ Skeletal muscle moves the skeleton.
■ Cardiac muscle forms the heart.
■ Smooth or visceral muscle forms the walls of the
abdominal organs
Generalized animal cell, sectional view. The main organelles are
shown.
Cell Structures
NAMe
plasma membrane
(PLAZ-ma)
Microvilli
(mī-krō-VIL-ī)
Nucleus
(NŪ-klē-us)
cytoplasm
(SĪ-tō-plazm)
DESCRIPTION
FUNCTION
outer layer of the cell
encloses the cell contents
short extensions of the cell membrane
absorb materials into the cell
large, dark-staining organelle
near the center of the cell
contains the chromosomes,
hereditary units
colloidal suspension that fills the cell
site of many cellular activities.
endoplasmic reticulum
network of membranes
(en-dō-PLAZ-mik re-TIK-ū-lum) within the cytoplasm.
ribosomes
(RĪ-bō-sōmz)
small bodies free in the cytoplasm
or attached to the ER
Mitochondria
(mī-tō-KON-drē-a)
large organelles with folded
membranes inside
Golgi apparatus
(GŌL-jē)
layers of membranes
lysosomes
(LĪ-sō-sōmz)
small sacs of digestive enzymes
peroxisomes
(per-OKS-i-sōmz)
surface projections
membrane-enclosed organelles
containing enzymes
structures that extend from the cell
cilia
(SIL-ē-a)
flagellum
rough ER sorts proteins
Smooth ER is involved lipid
synthesis.
manufacture proteins
convert energy from nutrients
into ATP
makes compounds containing
proteins, sorts and prepares these
compounds for transport to other
parts of the cell or out of the cell
digest substances within the cell
short, hair-like projections from the cell
long, whip-like extension from the cell
break down harmful
substances
move the cell or the fluids
around the cell
move the fluids around the
cell
moves the cel
(fla-JEL-um)
Terminology Key Terms
ATP
The energy compound of the cell that stores energy needed for cell activities;
adenosine triphosphate (a-DEN-ō-sēn trī-FOS-fāt)
carbohydrate The category of organic compounds that includes sugars and starches
kar-bō-HĪ-drāt
cell The basic structural and functional unit of the living organism, a microscopic unit that
sel combines with other cells to form tissues (root: cyt/o)
chromosome
A thread-like body in a cell’s nucleus that contains genetic information
KRŌ-mō-sōm
cytology
Study of cells
sī-TOL-ō-jē
cytoplasm The fluid that fills a cell and holds the organelles
SĪ-tō-plazm
DNA
The genetic compound of the cell, makes up the genes; deoxyribonucleic
(dē-ok- sē-rī-bōnū- KLĒ-ik) acid
enzyme
An organic substance that speeds the rate of a metabolic reaction
EN-zīm
gene
A hereditary unit composed of DNA and combined with other genes to form
jēn
the chromosomes
glucose
A simple sugar that circulates in the blood, the main energy source for
GLŪ-kōs
metabolism(roots: gluc/o, glyc/o)
Histology
Study of tissues
his-TOL-ō-jē
homeostasis A steady state, a condition of internal stability and constancy
hō-mē-ō-STĀ-sis
lipid
A category of organic compounds that includes fats (root: lip/o)
LIP-id
metabolism The sum of all the physical and chemical reactions that occur within an
me-TA-bō-lizm organism
mitosis Cell division
mī-TŌ-sis
nucleus The cell’s control center; directs all cellular activities
NŪ-klē-us
organ A part of the body with a specific function, a component of a body system
OR-gan
organelle A specialized structure in the cytoplasm of a cell
OR-ga-nel
RNA
An organic compound involved in the manufacture of proteins within cells;
ribonucleic(rī-bō-nū-KLĒ-ik) acid
tissue A group of cells that acts together for a specific purpose (roots: hist/o, histi/o)
TISH-ū