Chapter 1 Intro To Physiology And Homeostasis

Question 0

Definition of Anatomy

Answer 0

Anatomy is the study of the structure of the body.

Question 1

Definition of Physiology

Answer 1

Physiology is the study of the functions of living things.

Question 2

Definition of Cell

Answer 2

The cell, the fundamental unit of both structure and function in a living being, is the smallest unit capable of carrying out the processes associated with life.

Question 3

Definition of Organism

Answer 3

Organisms are independent living entities. The simplest forms of independent life are single-celled organisms such as bacteria and amoebas. Complex multicellular organisms, such as trees and humans, are structural and functional aggregates of trillions of cells.

Question 4

What are the levels of organization in the human body?

Answer 4

Chemical level: a molecule in the membrane that encloses a cell
Cellular level: a cell in the stomach lining
Tissue level: layers of tissue in the stomach wall
Organ level: the stomach
Body system level: the digestive system
Organism level: the whole body

Question 5

Definition of Cell Differentiation

Answer 5

During development of complex multicellular organisms such as humans, each cell differentiates, or becomes specialized to carry out a particular function.

Question 6

Definition of Enzyme

Answer 6

Enzymes are specialized proteins that speed up particular chemical reactions in the body

Question 7

Definition of Tissues

Answer 7

Cells of similar structure and specialized function combine to form tissues, of which there are four primary types: muscle, nervous, epithelial, and connective.

Question 8

Definition of Muscle Tissue

Answer 8

Muscle tissue consists of cells specialized for contracting, which generates tension and produces movement. The three types of muscle tissue include skeletal muscle, cardiac muscle, and smooth muscle.

Question 9

What are the three types of muscle tissue?

Answer 9

Skeletal muscle: which moves the skeleton
Cardiac muscle: which pumps blood out of the heart
Smooth muscle: which controls movement of contents through hollow tubes and organs, such as movement of food through the digestive tract.

Question 10

Definition of Nervous Tissue

Answer 10

Nervous tissue consists of cells specialized for initiating and transmitting electrical impulses, sometimes over long distances. These electrical impulses act as signals that relay information from one part of the body to another. Such signals are important in communication, coordination, and control in the body. Nervous tissue is found in the brain, spinal cord, nerves, and special sense organs.

Question 11

Definition of Epithelial Tissue

Answer 11

Epithelial tissue consists of cells specialized for exchanging materials between the cell and its environment. Any substance that enters or leaves the body proper must cross an epithelial barrier. Epithelial tissues is organized into two general types of structures: epithelial sheets and secretory glands. Only selective transfer of materials is possible between regions separated by an epithelial barrier. The type and extent of controlled exchange vary depending on the location and function of the epithelial tissue.

Question 12

Definition of Epithelial Sheets

Answer 12

Epithelial sheets are layers of tightly joined cells that cover and line various parts of the body. For example, the outer layer of the skin is epithelial tissue, as is the lining of the digestive tract. In general, epithelial sheets serve as boundaries that separate the body from its surroundings and from contents of cavities that open to the outside, such as the digestive tract lumen.

Question 13

Definition of Lumen

Answer 13

a lumen is the cavity within a hallow organ or tube

Question 14

Definition of Glands

Answer 14

Glands are epithelial tissue derivatives specialized for secreting. Glands are formed during embryonic development by pockets of epithelial tissue that invaginate (dip inward from the surface) and develop secretory capabilities. The two categories of glands are exocrine and endocrine.

Question 15

Definition of Exocrine Glands

Answer 15

During developement, if the connecting cells between the epithelial surface cells and the secretory gland cells within the invaginated pocket remain intact as a duct between the gland and the surface, an exocrine gland is formed. Exocrine glands secrete through ducts to the outside of the body. Examples are sweat glands and glands that secrete digestive juices.

Question 16

Definition of Endocrine Glands

Answer 16

If the connecting cells disappear during development and the secretory glands are isolated from the surface, an endocrine gland is formed. Endocrine glands lack ducts and release their secretory products, known as hormones, internally into the blood. For example, the pancreas secretes insulin into the blod, which transports this hormone to its sites of action throughout the body. Most cell types depend on insulin for taking up glucose (sugar).

Question 17

Definition of Secretion

Answer 17

Secretion is the release from a cell, in response to appropriate stimulation, of specific products that have been produced by the cell.

Question 18

Definition of Connective Tissue

Answer 18

Connective tissue is distinguished by having relatively few cells dispersed within an abundance of extracellular material. Connective tissue connects, supports, and anchors various body parts. It includes loose connective tissue that attaches epithelial tissue to underlying structures; tendons, which attach skeletal muscles to bones; bone, which gives the body shape, support and protection; and blood, which transports materials from one part of the body to another. Except for blood, the cells within connective tissue produce specific structural molecules that they release into the extracellular spaces between the cells.

Question 19

Definition of Organs

Answer 19

Organs consist of two or more types of primary tissue organized to perform a particular function or functions.

Question 20

Exocrine Glands vs. Endocrine Glands

Answer 20

Exocrine gland cells release their secretory product through a duct to the outside of the body (or to a cavity in communication iwth the outside) whereas endocrine gland cells release their secretory product (a hormone) directly into the blood.

Question 21

Definition of Body Systems

Answer 21

Groups of organs are further categorized into body systems. Each system is a collection of organs that perform related functions and interact to accomplish a common activity essential for survival of the whole body. The human body has 11 systems: circulatory, digestive, respiratory, urinary, skeletal, muscular, integumentary, immune, nervous, endocrine, and reproductive.

Question 22

Definition of External Environment

Answer 22

The external environment is the surrounding environment in which an organism lives.

Question 23

Definition of Internal Environment

Answer 23

The internal environment is the fluid that surrounds the cells and through which they make life-sustaining exchanges.

Question 24

Definition of Intracellular Fluid (ICF)

Answer 24

The fluid collectively contained within all body cells

Question 25

Definition of Extracellular Fluid (ECF)

Answer 25

The fluid outside the cells. Note that the ECF is outside the cells but inside the body. Thus, the ECF is the internal environment of the body. ECF is made up of two components the plasma and the interstitial fluid.

Question 26

What are the two components of ECF (extracellular fluid)?

Answer 26

Plasma: the fluid portion of the blood

Interstitial fluid: surrounds and bathes the cells.

Question 27

What makes up the Circulatory System?

Answer 27

(heart, blood vessels, and blood) transports materials such as nutrients, O2, CO2, wastes, electrolytes, and hormones from one part of the body to another

Question 28

What makes up with digestive system?

Answer 28

(Mouth, esophagus, stomach, intestines, and related organs) breaks down dietary food into small nutrient molecules that can be absorbed into the plasma for distribution to the body cells. It also transfers water and electrolytes from the external environment into the internal environment. It eliminates undigested food residues to the external environment in the feces.

Question 29

What makes up the Respiratory System?

Answer 29

(lungs and major airways) gets O2 from and eliminates CO2 to the external environment. By adjusting the rate of removal of acid-forming CO2, the respiratory system is also important in maintaining the proper pH of the internal environment.

Question 30

What makes up the Urinary System?

Answer 30

(kidneys and associated “plumbing”) removes excess water, salt, acid, and other electrolytes from the plasma and eliminates them in the urine, along with waste products other than CO2

Question 31

What makes up the skeletal System?

Answer 31

(bones and joints) provides support and protection for the soft tissues and organs. Together with the muscular system, the skeletal system enables the body and its parts to move. Furthermore, the bone marrow–the soft interior portion of some types of bone–is the ultimate source of all blood cells.

Question 32

what makes up the muscular system?

Answer 32

(skeletal muscles) moves the bones to which the skeletal muscles are attached.

Question 33

What is the integumentary system composed of?

Answer 33

(skin and related structures) serves as an outer protective barrier that prevents internal fluid from being lost from the body and foreign micro-organisms from entering. This system is also important in regulating body temperature.

Question 34

What makes up the immune system?

Answer 34

(white blood cells and lymphoid organs) defends against foreign invaders such as bacteria and viruses and against body cells that have become cancerous. It also paves the way for repairing or replacing injured or worn-out cells.

Question 35

What is the nervous system composed of?

Answer 35

(brain, spinal cord, nerves, and sense organs) is one of the body’s two major regulatory systems. In general, it controls and coordinates body activities that require swift responses. It is especially important in detecting changes in the external environment and initiating reactions to them.

Question 36

What is the endocrine system composed of?

Answer 36

(all hormone-secreting glands) is the other major regulatory system. In contrast to the nervous system, the endocrine system in general regulates activities that require duration rather than speed, such as growth. It is especially important in controlling the blood concentration of nutrients and, by adjusting kidney function, controlling the volume and electrolyte composition of the ECF.

Question 37

What is the reproductive system composed of?

Answer 37

(male and female gonads - testes and ovaries - and related organs) is not essential for homeostasis and therefore is not essential for survival of the individual. It is essential for perpetuating the species.

Question 38

Plasma

Answer 38

The fluid portion of the blood

Question 39

Interstitial fluid

Answer 39

fluid which surrounds and bathes the cells.

Question 40

Homeostasis

Answer 40

Maintenance of a relatively stable internal environment

Question 41

Many factors of the internal environment must be homeostatically maintained. They include the following:

Answer 41

1. concentration of nutrients 2. concentration of O2 and CO2 3. concentration of waste products 4. pH 5. concentrations of water, salt, and other electrolytes 6. volume and pressure and 7. temperature

Question 42

Homeostatic control system

Answer 42

a functionally interconnected network of body components that operate to maintain a given factor in the internal environment relatively constant around an optimal level.

Question 43

To maintain homeostasis, the control system must be able to:

Answer 43

1. detect deviations from normal in the internal environmental factor that needs to be held within narrow limits; 2. integrate this information with any other relevant information; and 3. make appropriate adjustments in the activity of the body parts responsible for restoring this factor to its desired value.

Question 44

Intrinsic homeostatic control

Answer 44

Intrinsic, or local, controls are built into or are inherent in an organ (intrinsic means within).

Question 45

example of intrinsic homeostatic control

Answer 45

as an exercising skeletal muscle rapidly uses up O2 to generate energy to support its contractile activity, the O2 concentration within the muscle falls. This local chemical change acts directly on the smooth muscle in the walls of the blood vessels supplying the exercising muscle, causing the smooth muscle to relax so that vessels dilate. As a result, increased blood flows through the dilated vessels into the exercising muscle, bringing in more O2. This local mechanism helps maintain an optimal level of O2 in the fluid immediately around the exercising muscle’s cells.

Question 46

Extrinsic homeostatic control

Answer 46

most factors in the internal environment are maintained by extrinsic, or systemic, controls, which are regulatory mechanism initiated outside an organ to alter the organ’s activity. Extrinsic control of the organs and body systems is accomplished by the nervous and endocrine systems, the two major regulatory systems.

Question 47

Difference between intrinsic and extrinsic homeostatic controls

Answer 47

Extrinsic control permits coordinated regulation of several organs toward a common goal; in contrast, intrinsic controls serve only the organ in which they occur.

Question 48

example of extrinsic homeostatic control

Answer 48

to restore blood pressure to the proper level when it falls too low, the nervous system acts simultaneously on the heart and blood vessels throughout the body to increase blood pressure to normal.

Question 49

Negative feedback

Answer 49

a change in a homeostatically controlled factor triggers a response that seeks to restore the factor to normal by moving the factor in the opposite direction of its initial change-that is, a corrective adjustment opposes the original deviation from the normal desired level.

Question 50

Positive Feedback system

Answer 50

the output enhances or amplifies a change so that the controlled variable continues to move in the direction of the initial change. Example: in the birth of a baby.