1. Ch. 8 Cell Structure & Function
Lesson 2 How are Cells Specialized?

2. Different Cells for Different Jobs
All multicellular organisms have specialized cells
that work together.
Complex organisms have many types of cells.
Each cell has special structures that allow it to
carry out specific tasks.
A group of cells that has a common structure
function is called a tissue.
Epithelial tissues:
*sheet of cells that
cover surfaces
*line certain body
cavities and blood vessels
*usually smooth

3. Connective tissues:
*join other tissues together
*stores fat and makes blood cells
*includes bone, blood, and cartilage
*made of specialized cells and fibers
that stick to living cells
Muscle tissues:
*work together to move body
*create movement in one direction only (either
getting longer or shorter)
Nervous tissue:
*produces electrical impulses and sends signals
*routed through nervous tissue
*some send signals while others protect and
provide with nutrients

4. Body functions performed by special structures
called organs
Organs:
*made up of several tissue types that work
together to perform one or more functions
*example-plant’s leaves, roots, flowers
Three human organs:
*brain-
*heart-
*liver-
*skin-protect from injury and retain moisture
Some organs perform more than one function
*kidneys-remove waste and control blood
pressure

5. Relationship among cells, tissues, and organs
*tissues are groups of cells with
common structures and functions
*organs are made of different types of
tissues that work together
Organ Systems
Groups of organs that work together to perform
complex tasks
The more complex the organism,
the greater the number of organ
systems needed to survive.
Humans have 11 organ systems.
Some work for more than one
organ system.

6. Circulatory system
Carries hormones made in the endocrine system
throughout the body
Carries blood and oxygen to the body and
removes carbon dioxide and other wastes
Helps keep body temperature constant
Includes heart, arteries, veins, and blood
Connects to the Urinary system at the kidneys
*helps regulate water and salt in blood, as
well as remove liquid wastes
Musculoskeletal system
Supports all parts of body and
allows movement of different parts
Bones anchor body parts and provide structure

7. Contracting your muscles make body parts move
Generates warmth for body (reason why you feel
warmer when you exercise)
Nervous system
Brain is headquarters of
nervous system
Senses feed information into
brain
Brain process and responds to information by
sending signals down nerves to muscles
Brain control other organ systems
Respiratory system
Brings oxygen into body
Removes carbon dioxide from body

8. Endocrine System
Chemical messenger system that makes and
sends out hormones throughout the body
Hormones have many functions
*act as messages
*travel through bloodstream
*picked up only by certain cells
*regulating growth and blood sugar
Growth hormone-cause
dramatic changes in muscles
and bones as you grow
Plants use hormones to control
growth and other functions

9. What makes a multi-celled organism different
from one that is single-celled?
Only multi-celled organisms have cells that work together to form specific functions.