1. Unit 5: Body Systems
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2. Levels of Organization
Recall that there are 6 characteristics of living things, we are focusing on two for Unit 5:
all living things are made up of cells
all living things are organized

4. Add tissue to your index
Tissues are groups of similar types of cells in multicellular organisms that work together to carry out specific tasks
Humans, like most other animals, have four main types of tissue: muscle, connective, nervous, and epithelial
Add tissue to your index

5. made up of layers of tightly packed cells that line the surfaces of the body
examples of epithelial tissue include the skin, the lining of the mouth and nose, and the lining of the digestive system
made up of many different types of cells that are all involved in supporting and binding other tissues of the body
examples include tendon, cartilage, and bone. Blood is also classified as a specialized connective tissue
made up of bands of cells that contract and allow movement
made up of nerve cells that sense stimuli and transmit signals
nervous tissue is found in nerves, the spinal cord, and the brain

6. Add organs and organ systems to your index
Organs are groups of different tissues working together to perform a particular job.
Organ systems are groups of different organs that work together to complete a series of tasks.
Add organs and organ systems to your index

7. Multicellular organisms usually have many organ systems that work together to carry out all the jobs needed for the survival of the organism.

8. Right Now Copy down your homework Take out your homework Today’s Plan
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Continue notes on Body Systems

9. Place this tape-in into your notebook and label each level of organization

11. Systems may interact with other systems
Systems may have subsystems and be part of larger complex systems

12. The Circulatory System
includes the heart, blood vessels and blood
transports oxygen, hormones and nutrients to the body’s cells
moves waste and carbon dioxide away from cells

13. The Excretory System includes the kidneys and bladder
removes water, salts, and waste products from blood and body
controls pH
controls water and salt balance

14. The Digestive System
includes the stomach, small intestine, and large intestine
digests foods
absorbs nutrients, minerals, vitamins, and water

15. The Respiratory System
includes the trachea, larynx, pharynx, and lungs
brings air to sites where gas exchange can occur between the blood and cells (around the body) or blood and air (in the lungs)

16. The Muscular System
includes cardiac (heart) muscle, skeletal muscle, smooth muscle, and tendons
involved in movement and heat production

17. The Nervous System includes the brain, spinal cord, and nerves
collects, transfers, and processes information

18. The Endocrine System includes all of the glands of the human body
produces hormones
regulates metabolism, growth and development, sleep and mood

19. Homeostasis
What is the first sign that you may be sick?

20. Homeostasis
The systems in your body work together to maintain homeostasis Homeostasis is the ability to maintain constant internal conditions when outside conditions change

21. System Interactions
Nutrients are processed when the digestive, muscular, and circulatory systems work together.
The respiratory, circulatory, muscular, and digestive systems work together and process oxygen and move wastes from the body.
The nervous system communicates with the muscular and skeletal systems and coordinates movement and responds to stimuli.

22. Unit 5 B: Signals in Your Body
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23. Add sensory receptors to your index
Sensory receptors are specialized cells to detect specific stimuli
Interoceptors – detect stimuli inside the body
Include receptors for blood pressure, blood volume, and blood pH
Directly involved in homeostasis
Exteroceptors – detect stimuli outside the body
Include receptors for taste, smell, vision, hearing, and equilibrium
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24. Types of Sensory Receptors
Chemical receptors – respond to chemicals
Taste, smell, blood pH
Photo receptors – respond to light energy
Vision (light)
Mechanical receptors – stimulated by mechanical forces
Hearing, gravity, motion, body position

25. Thermoreceptors – stimulated by changes in temperature
Located in the hypothalamus (region of brain) and skin
Nociceptors (Pain receptors) – free nerve endings that are stimulated by chemicals released by damaged tissue
Alert us to possible danger

26. How Sensation Occurs There are three steps to interpreting sensation:
Detection occurs when environmental changes stimulate sensory receptors
Sensation occurs when nerve impulses arrive at the cerebral cortex of the brain
Perception occurs when the brain interprets the meaning of stimuli
The cerebral cortex plays a key role in memory, attention, perception, awareness, thought, language, and consciousness

27. We are aware of a reflex action when sensory information reaches the brain
The brain integrates this information with other information received from other sensory receptors

29. Sense of Taste
Taste buds contain chemoreceptors and are located primarily in the tongue
Different receptors exist for salty, sour, bitter, sweet tastes and umami (savory)

30. How does the Brain Receive Taste Information?
Detection – food makes contact with your taste buds
Sensation – three different nerves in your tongue send signals to your brain
Perception – your brain interprets these signals and tells you what you are tasting

32. Sense of Smell
80-90% of what we perceive as taste is actually due to smell
Olfactory cells
Chemoreceptors are located high in the nasal cavity

33. How does the Brain Receive Odor Information?
Detection – during respiration scent molecules enter your nose
Sensation – nerve fibers in your nose send signals to your brain via the olfactory tract
Perception – your brain determines what you are smelling or an odor’s “signature”

35. Sense of Vision Vision requires the work of the eyes and the brain
It is believed that at least 1/3 of the cerebral cortex takes part in processing vision

36. How does the Brain Receive Sight Information?
Detection – light enters the eye, it is focused on photoreceptors in the retina
Sensation – signal is sent from optic nerve to the visual cortex
Perception – your visual cortex deciphers the image

38. Sense of Hearing
The ear has two sensory functions- hearing and balance (equilibrium)
Sensory receptors for both of these are located in the inner ear
Each consists of hair cells with stereocilia (long microvilli) that are sensitive to mechanical stimulation (mechanoreceptors)

39. How does the Brain Receives Sound Information?
Detection – sound waves enter the auditory canal and your ear drum vibrates
Sensation – the vibrations send signals to your auditory cortex
Perception – your brain interprets the sound

41. Sense of Touch
You probably think of the sense of touch as relating to your skin, after all, you have about 5 million sensory nerve receptors in your skin
When the touch, pain or heat sensors in your skin are stimulated, they send electrical pulses to your neurons, special cells that relay electrochemical impulses 

42. How does the Brain Receive Feeling Information?
Detection – contact is made with sensory receptors
Sensation – sensory receptors send signals to spinal cord
Perception – brain receives and translates signal from spinal cord to determine feeling (touch, pain, heat, etc.)