A&P. Chapter 1. The Human Organism

BIOS 357 Human Anatomy and Physiology

Chapter 1: The Human Organism

Learning Outcomes

1)      Define the terms anatomy and physiology and identify the different ways in which they can be studied.

2)      Describe the chemical, organelle, cell, tissue, organ, organ system, and whole organism levels of organization.

3)      List the 11 organ systems, and indicate the major functions of each.

4)      List the characteristics of life.

5)      Explain the importance of studying other animals to help us to understand human anatomy and physiology.

6)      Define homeostasis, and explain homeostasis using the terms variable, set point, and normal range.

7)       Describe negative- and positive-feedback systems and their relationship to homeostasis.

8)      Describe the anatomical position, and use directional terms to describe the location of specific body structures.

9)      List the terms used to describe different regions or parts of the body.

10)  Name and describe the three major planes of the body or of an organ.

11)  Define the terms thoracic cavity, abdominal cavity, and mediastinum.

12)   Define serous membrane, and explain the relationship between parietal and visceral serous membranes.

13)  Name the membranes that line the walls and cover the organs of each body cavity, and name the fluid found inside each cavity.

14)  Define mesentery, and describe its function.

15)  Define the term retroperitoneal, and list examples of retroperitoneal organs.

Summary

1.1)            Anatomy and Physiology

1)      Anatomy is the study of the structures of the body.

2)      Systemic anatomy is the study of the body by organ systems. Regional anatomy is the study of the body by areas.

3)      Surface anatomy uses superficial structures to locate deeper structures, and anatomical imaging is a non-invasive method for examining deep structures.

4)      Physiology is the study of the processes and functions of the body. It can be approached according to the organism involved or level of organization.

1.2)            Structural and Functional Organization

1)      The human body can be organized into six levels:

a.      Chemical

b.      Cell

c.       Tissue

d.      Organ

e.      Organ System

f.        Organism

2)      The 11 organ systems are:

a.      Integumentary

b.      Skeletal

c.       Muscular

d.      Nervous

e.      Endocrine

f.        Cardiovascular

g.      Lymphatic

h.      Respiratory

i.        Digestive

j.        Urinary

k.       Reproductive

1.3)            Characteristics of Life

1)      The characteristics of life include organization, metabolism, responsiveness, growth, development, and reproduction.

1.4)            Homeostasis

1)      Homeostasis is the existence and maintenance of a relatively constant internal environment.

2)      Variables, such as body temperature, are maintained around a set point, resulting in a normal range of values.

1.4A)   Negative Feedback

1)      Negative-feedback mechanisms maintain homeostasis.

2)      Many negative-feedback mechanisms consist of a receptor, a control center, and an effector.

1.4B)    Positive Feedback

1)      Positive-feedback mechanisms make deviations from normal even greater.

2)      Although a few positive-feedback mechanisms normally exist in the body, most positive-feedback mechanisms are harmful.

1.5)            Terminology

1)      Body Positions

a.      A human standing erect with the face directed forward, the arms hanging to the sides, and the palms facing forward is in the anatomical position.

b.      A person lying face upward is supine and face downward is prone.

2)      Directional Terms

a.      Directional terms always refer to the anatomical position, regardless of the body’s actual position.

3)      Body Parts and Regions

a.      The body can be divided into the upper limbs, lower limbs, head, neck, and trunk.

b.      The abdomen can be divided superficially into four quadrants or nine regions that are useful for locating internal organs or describing the location of a pain.

4)      Planes

a.      A sagittal plane divides the body into left and right parts, a transverse plane divides the body into superior and inferior parts, and a frontal plane divides the body into anterior and posterior parts.

b.      A longitudinal section divides an organ along its axis, a cross section cuts an organ at a right angle to the long axis, and an oblique section cuts across the long axis at an angle other than a right angle.

5)      Body Cavities

a.      The thoracic cavity is bounded by the ribs and the diaphragm. The mediastinum divides the thoracic cavity into two parts.

b.      The abdominal cavity is bounded by the diaphragm and the abdominal muscles.

c.       The pelvic cavity is surrounded by the pelvic bones.

6)      Serous Membranes

a.      Serous membranes line the trunk cavities. The parietal part of a serous membrane lines the wall of the cavity, and the visceral part is in contact with the internal organs.

b.      The serous membranes secrete serous fluid that fills the space between the parietal and visceral membranes. The serous membranes protect organs from friction.

c.       The pericardial cavity surrounds the heart, the pleural cavities surround the lungs, and the peritoneal cavity surrounds certain abdominal and pelvic organs.

d.      Mesenteries are parts of the peritoneum that hold the abdominal organs in place and provide a passageway for blood vessels and nerves to organs.

e.      Retroperitoneal organs are located “behind” the parietal peritoneum. The kidneys, the adrenal glands, the pancreas, parts of the intestines, and the urinary bladder are examples of retroperitoneal organs.