Download Answers to Mastering Concepts Questions

Answers to Mastering Concepts Questions
Chapter 27
27.1
1. Anatomy is the study of the physical arrangement of the body’s parts; physiology explains how
those parts.
2. Specialized cells form tissues. Multiple tissues working together form organs, and organ
systems are groups of related organs that interact to produce a specific body process.
3. A fertilized egg divides to form a blastula. Then one end of the hollow ball of cells pushes
inward, forming a gastrula with three primary tissue layers. Each tissue layer contributes to
several organs that are related in organ systems.
27.2
1. You would find epithelial tissue as sheets of cells that coat and line the body’s external and
internal surfaces, including organs and blood vessels.
2. Epithelial tissues are named according to the shapes of their cells and the number of cell
layers.
3. In connective tissue, the cells are held within or embedded within the nonliving extracellular
matrix.
4. The six types of connective tissue are:
- Loose connective tissue: fibroblasts and white blood cells in a matrix of elastin and collagen
fibers.
- Dense connective tissue: fibroblasts held in a matrix of dense elastin and collagen fibers.
- Adipose tissue: fat cells embedded in a small amount of extracellular matrix.
- Blood: red and white blood cells and platelets suspended in a liquid matrix called plasma.
- Cartilage: chondrocytes in a network of fine collagen fibers.
- Bone: bone cells held within a matrix composed of collagen and minerals.
5. The two main cell types in nervous tissue are neurons and neuroglia.
6. The three types of muscle tissue are:
- skeletal muscle: cells have many nuclei and have a striated appearance. Skeletal muscle is
under voluntary control, and most of it attaches to bone.
- smooth muscle: each cell has one nucleus and no striations. Smooth muscle forms part of
many internal organs and is under involuntary control.
- cardiac muscle: cells are striated and each contains one nucleus. Cardiac muscle cells are
connected electrically so that they contract simultaneously. Cardiac muscle forms much of the
heart and is under involuntary control.
27.3
1. Examples of interactions between organ systems include:
- the circulatory system brings blood to the urinary system, where the blood is cleansed. Fluids
then return to the circulatory system. The functions of the urinary system are monitored by
endocrine glands and controlled by hormones.
- the respiratory system exchanges gases with the bloodstream. The nervous system monitors
the breathing rate, which is under the control of voluntary muscles and involuntary muscles. The
breathing rate is also influenced by hormones.
- the digestive system breaks food down into particles that are absorbed into the bloodstream and
carried to cells that need nutrients (or stored in the liver and in fat deposits). The digestive system
is controlled by hormones and influenced by the nervous system.
2. Here are the five general functions of life and the organ systems that primarily contribute to
them:
Communication: nervous and endocrine systems
Movement and support: muscular and skeletal systems
Acquiring energy: circulatory, respiratory, and digestive systems
Protection: integumentary, urinary, and immune systems
Reproduction: reproductive system (although all systems contribute indirectly to this function).
27.4
1. Interstitial fluids form part of the body’s internal environment.
2. An organism that fails to maintain homeostasis will stop functioning and will eventually die.
3. In negative feedback, the product of a process turns off its own production. In positive
feedback, the product of a process stimulates its own production.
27.5
1. The layers of human skin and the tissue types they are made of are:
- epidermis: made of stratified squamous epithelium;
- dermis: made of dense connective tissue.
2. Specialized cells of the epidermis include keratinocytes that produce keratin and melanocytes
that produce melanin and affect the skin’s color. Examples of specialized cells of the dermis
include those that make up the hair follicles, sweat glands, mammary glands, and sebaceous
glands.
3. The integumentary system blocks the entry of foreign organisms and foreign objects into the
body. It also prevents the loss of body fluids and helps to maintain body temperature through the
constriction and dilation of blood vessels and erection of hair or feathers in animals that have
them. The production of Vitamin D in skin helps to keep the skeleton strong.