From Cells to Organ Systems

• Cells combine to form tissues, and tissues combine to form organs

• Cells combine to form four primary tissues– Epithelial tissue– Connective tissue– Muscle tissue – Nervous tissue

• Two types: – membranous epithelia

• form the coverings or linings of organs

– glandular epithelia• form exocrine and endocrine glands

Epithelium

Epithelial Tissue

Epithelial Tissue

Epithelium-Human Stomach

Glandular Epithelia

• Epithelial tissues illustrate a basic biological principle: that structure closely correlates with function

• Figure 4.4

• Binds the cells and organs of the body together – All connective tissues

consist of two basic components: cells and extracellular fibers

• Two types of connective tissue are: – Connective tissue

proper – Specialized connective

tissue

Section 4-1Connective Tissue

Connective Tissue

Connective

Tissue

• An important structural component of organs – Consists of two types:

• Dense connective tissue • Loose connective tissue

Connective Tissue

Connective Tissue

• Perform specific functions essential to homeostasis

• The body contains three types of specialized connective tissue:

• Cartilage• Bone• Blood

Specialized Connective Tissues

•Cartilage –Consists of specialized cells embedded in a matrix of extracellular fibers and other extracellular material

•Blood –Contains blood cells, platelets, plasma

Osseous Tissue• Bone

– Consists of bone cells (osteocytes) and a calcified cartilage matrix• Two types of

bone tissue exist: spongy and compact

Osseous Tissue

• Consists of specialized cells that contract when stimulated

• The body has three types of muscle tissue:•Skeletal (voluntary)•Cardiac (involuntary)•Smooth muscle (involuntary)

Muscle Tissue

Muscle Tissue

Muscle

Tissue

Nervous Tissue

• Contains specialized cells that conduct impulses

• Conducting cells, called neurons, transmit impulses from one region of the body to another.

• Nonconducting cells, neuroglia, are a type of nervous system connective tissue.

Nerve Tissue

Nerve Tissue

Organ Systems

• Tissues combine to form organs.– Organs are discrete structures that have

evolved to perform specific functions – Most organs do not function alone, they are

part of a group of cooperative organs, called an organ system.