Transcript Human Body Introduction

 Do all of your cells do the same thing?
 Give a few examples.
 There are nearly a hundred trillion cells that make up
the human body.
 Every cell is an independent unit and an
interdependent part of a larger community.
 All the body systems work together so the body
functions properly.
 An organism is a living thing made of a
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group of organs systems.
Organ systems are living things made of a
group of organs that contribute to a
specific function within the body.
Organs are living things made of tissues
that work together to perform a specific,
complex function.
Tissues are living things made of a group
of cells with similar structures and
functions.
Cells are the smallest unit of life.
 Different tissue types work together within organs:
 Muscle tissue (most abundant): controls internal
movements of materials (ex: blood, food)
 Epithelial tissue: closely packed cells covering the
surface of the body and line internal organs (ex: inside
chambers of heart, glands)
 Connective tissue: holds organs in place and binds
different parts of the body together (ex: tendons,
ligaments)
 Nervous tissue: receives messages from the body’s
external and internal environments, analyzes the data,
and directs response (ex: controls heart beat)
 The eleven organ systems of the human body work
together to maintain homeostasis.
1. Nervous
7. Integumentary
2. Respiratory
8. Digestive
3. Excretory
9. Skeletal
4. Muscular
10. Circulatory
5. Endocrine
11. Reproductive
6. Lymphatic
 Try to identify as many systems as possible on picture…
 What are some organs in each system?
Figure 35-2 Human Organ Systems Part I
Section 35-1
Nervous System
Integumentary System
Skeletal System
Muscular System
Circulatory System
Figure 35-2 Human Organ Systems Part 2
Section 35-1
Respiratory System
Endocrine System
Digestive System
Reproductive System
Excretory System
Lymphatic System
 Nervous: coordinates the body’s response to change in the internal
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and external environments.
Integumentary: serves as a barrier against infection and injury, helps
to regulate body temperature, provides protection against UV radiation
from the sun
Respiratory: provides oxygen needed for cellular respiration and
removes excess carbon dioxide from the body
Digestive: converts foods into simpler molecules that can be used by
the cells of the body, absorbs food
Excretory: eliminates waste products of metabolism from the body,
maintains homeostasis
Skeletal: supports the body, protects internal organs, allows
movement, stores mineral reserves, provides a site for blood cell
formation
 Muscular: works with skeletal system to produce voluntary movement,
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helps to circulate blood and move food through the digestive system
Circulatory: brings oxygen, nutrients, and hormones to cells, fights
infection, regulates body temperature
Endocrine: controls growth, development, metabolism, and
reproduction
Reproductive: produces reproductive cells (in females, nurtures and
protects developing embryo
Lymphatic: helps protect the body from disease, collects fluid lost from
blood vessels and returns the fluid to the circulatory system
Interest Grabber
 While walking along a dusty path, you begin to cough. As
you continue your walk, a small insect comes flying toward
you. You blink and then duck so that it misses you. These
actions are just a few examples of homeostasis.
 Homeostasis is the process by which organisms keep internal
conditions relatively constant despite changes in their
external environments.
 1. List three other examples of homeostasis that occur in organisms.
 2. Why is homeostasis important to an organism?
 Your organ systems are working together constantly
trying to maintain a controlled, stable internal
environment.
 Remember: Your cells need a constant supply of
nutrients and oxygen at a stable temperature for
cellular respiration, and then the waste products need
to be removed.
Feedback Inhibition
Thermostat senses temperature
change and switches off heating
system
Heating system turns on
Room temperature decreases
Thermostat senses temperature
change and switches on heating
system
 The process by which the product of a system shuts
down the system or limits its operation.
 When the system is switched on, it produces a product
that changes the internal environment = “feedback”
 When the change (feedback) is detected, it shuts down
the system = “inhibition”
 This system is usually automatic and very stable.
 Biological systems achieve homeostasis through
feedback inhibition.
 All that is needed is a system that regulates some
aspects of the cellular environment, and the system
responds to feedback by switching on or off as needed.
 Body temperature remains stable with a balance of heat
production and heat loss. The hypothalamus in your brain
contains nerve cells that monitor skin temperature and core
temperature. If core temperature drops, the hypothalamus
produces chemical signals throughout the body to speed up
activities producing heat. When the nerve cells detect a
temperature rise, the feedback inhibits the production of the
chemical signals and prevents the temperature from rising too
high.
 If you’re very cold, your hypothalamus releases chemical signals
for your muscles to shiver involuntarily, producing heat until
your body temperature reaches normal again.
 If you’re too warm, your hypothalamus slows down cellular
activities, making you feel tired/sluggish and you sweat, which
cools your body surface by evaporation, until you reach a normal
temperature again.