Review for exam 3
LEARNING OBJECTIVES – Ch 28
Characterize the symmetry of animals. -The back side is called the dorsal, the front is called the ventral.
Bi lateral symmetry developed we had increased cephalazation. The development of a head. And led to
the separation of body cavities. Thoratic, abdominal, and pelvic. These keep the organs separated.
Understand the evolutionary importance of bilateral symmetry. It lead to cephalazation, the
development of the head. It allows parts of the body to evolve in different ways, permitting the
segregation of organs in different parts of the body.
Understand cells, tissues, organs, and organ systems. Cells- germ layers in the developing embryo,
there are three types of tissues: Ectoderm, mesoderm, and endoderm, these eventually develop into
all of the tissues we have in our body. Four broad categories of tissues occur in adults: epithelium,
connective, tissue, muscle tissue, and nerve tissue. Tissues, which are a bunch of cells grouped
together, come together and make an organ and then organs come together and make an organ
system. The human body has eleven different organ systems; the skeletal system, circulatory system,
endocrine system, nervous system, respiratory system, lymphatic and immune system, digestive
system, urinary system, skin or integumentary system, muscular system, and the reproductive
Discuss the different types of epithelium and their functions. Epithelium is protective tissue, it lines and
covers body surfaces. Epithelium provides three different functions: It protects tissues from
dehydration and damage, it provides sensory surfaces, and it secretes substances.
Types of epithelial cells and tissues:
Squamous- lining of lungs, capillary walls, and blood vessels. Function: Flat and thin cells provide a
thin layer across which diffusion can really occur. The cells from viewed from the surface look like tile.
Cuboidal- Lining of some glands and kidney tubles, covering of ovaries. Function: cells rich in specific
transport channels, functions in secretions and specific absorption.
Columnar- Surface lining of stomach, intestines, and parts of respiratory tracts. Functions: Thicker cell
layer, provides protection and functions in secretion and absorption.
Squamous- outer layer of skin; lining of mouth. Function: Tough layer of cells; provides protection
Columnar- lining parts of respiratory tract . functions in secretion of mucus; dense with cilia that aid
the movement of mucus; provides protection.
Connective tissue supports the body
Dense structural materials and immune defense, connective tissue is derived from mesoderm and falls
into three functional categories.