1. The study of the human body
The Skin-coverings
The skeletal system-support
The muscular system-movement

2. Structure fits function
The structure of living organisms is organized in a series of hierarchical levels
Atoms
Molecules
Cells
Tissue –group of the same cells doing a specific job-muscle tissue
Organ-two or more tissues working together for a specific job- heart
Organ system- different organs working together- digestive system
Organism- a living thing

8. Structure fits function

9. Four basic tissues
In almost all animals, most of the cells of the body are organized into tissues
4 main types
Epithelial- covers the body and lines organs and cavities
Skin-sheets of tightly packed cells
Connective-binds and supports other tissues
Ligaments, tendons, bones, cartilage, blood, fat
Muscle-movement
Skeletal, smooth-walls of internal organs, cardiac
Nervous-communication
Neurons, supporting cells

10. Organs working together make up Organ systems
The organs of humans and most other animals are organized into organ systems
Teams of organs that work together to perform vital body functions
Each organ system is coordinated to work together for the survival of the organism
Anatomy- study of the structure of the organs in organisms
Physiology- study of the function of the organs in organisms

11. Organ systems of the body
Integumentary system- skin, hair, nails, oil and sweat glands
Skeletal system-support body and anchors muscles
Muscular system- moves the body

12. Organ systems of the body
Digestive system-breaks down food and absorbs nutrients
Circulatory system- transports substances throughout body
Respiratory system- exchanges O2 and CO2 between blood and air
Urinary system- rids body of cellular wastes
Nervous system- processes sensory information and controls responses
Immune and Lymphatic system-defends against disease

13. Organ systems of the body
Endocrine system-secretes hormones that regulate the body
Reproductive system- produces gametes and offspring

14. The Skin- integument coverings of the body
Our skin is divided into two main layers
Outer epidermis-composed of about 20 layers of dead cells
Purpose is to provide mechanical barrier from microbes, and is a waterproof protective cover
Protein keratin deposited into cells & makes it waterproof- same protein makes up our hair, nails
Dermis- living layer under the epidermis
Elastic and dense fibers-allow stretching
Blood, nerves –temp & pain sensations
Fat storage- insulation, protection of organs

15. The skin

16. The skin
Our body continuously renews the cells of the epidermis, shedding old cells and growing new ones-about every 2 weeks
Such turnover requires rapid cell division increasing the risk of an error-resulting in cancer
Compared to other body parts, our skin is exposed to many carcinogens- cancer causing substances- UV light, smoke in lungs
Consequently-80% of all cancers-(skin, lung, breast) come from epithelial tissue

17. Some examples of organs lined with epithelial tissue:
Figure
Some examples of organs lined with epithelial tissue:
Heart
Lung
Stomach
Small intestine
Epithelial cells
Large intestine
Epithelial tissue lining esophagus
Urinary bladder
Figure 21.3 Epithelial tissue (step 3)
Epithelial tissue lining small intestine

18. The skeletal system
Composed of bones, ligaments, tendons, cartilage- all made of
Connective tissue-lots of protein fibers in a semi-solid or solid foundation.
Designed to hold together or support other tissues
Bones support the muscles which move the skeleton
Ligaments connect bones together
Tendons hold muscles to bones
Cartilage acts as a cushion between bones
Functions of the skeleton
Support and shape
Protection of organs
Attachment of muscles
Blood cell production-marrow
Mineral storage

19. (a) Loose connective tissue (d) Fibrous connective tissue
Figure 21.4
(a) Loose connective tissue
(b) Adipose tissue
(c) Blood
Figure 21.4 Types of connective tissue
(d) Fibrous connective tissue
(f) Bone
(e) Cartilage

20. Skeletal system The skeleton is divided into two main regions
The axial skeleton is composed of:
Skull bones
Vertebrae
Rib cage
The appendicular skeleton is composed of:
Bones of shoulder and arm
Bones of hips and legs

21. Joints of the body
Joints are categorized by the amount of movement that is created
No movement- skull bones
Slight movement- ribs, vertebrae
A lot of movement- most joints- joined by ligaments and surrounded by synovial fluid “oil”
Knee, shoulder, neck, hands, feet

22. Muscular system Muscle makes up most of the tissue in an animal’s body
has specialized proteins arranged into a structure that contracts when stimulated by a signal from a nerve.
Functions include:
Movement- of skeleton, organs, and heart
Maintain an upright posture
Maintain an internal temperature
Three main types of muscle tissue
Striated- also called skeletal muscle- striped in appearance
lines the skeleton and moves the bones using tendons

23. Striated muscle

24. Striated muscle attached to bones by tendons,
responsible for voluntary movements, and
striated because the contractile proteins form a banded pattern.
The contractile proteins are called actin and myosin threads that make up a muscle cell (fiber)
Actin are thin threads
Myosin are thick threads
The overlapping of the threads is responsible for the striations that contract causing movement
Nerves stimulate muscles, muscles contract

25. Sliding filament theory of muscle contraction
Each muscle cell (called a sarcomere) is composed of alternating light thin actin filaments & dark thick myosin filaments.
When stimulated by a nerve, ATP energy binds to a myosin head causing it to attach to an actin binding site which pulls the actin threads towards the center causing a contraction of the muscle.
Working or exercising muscles increases the size of each cell not the number of cells.
When muscles do work, heat is produced which helps maintain internal body temp.

26. Actin and myosin threads

27. Cardiac muscle found only in heart tissue,
composed of cells that are branched and striated,
involuntary, and
responsible for the contraction of the heart
Intercalated discs are junctions between heart cells that act to coordinate all the cells to work together making the heart an efficient pump

28. (b) Cardiac muscle Junction between two cells- intercalated disks
Figure 21.5b
Junction between two cells- intercalated disks
Muscle
fiber
Nucleus
Figure 21.5 Three types of muscle tissue (part 2)
(b) Cardiac muscle

29. Smooth muscle named for its lack of obvious stripes,
found in the walls of various organs such as intestines and blood vessels, and
involuntary.