1 Anatomy and Physiology
1
UNIT 1: ANATOMY
Intended Learning Outcomes
a. Define anatomy and physiology and explain their relationship.
b. Define homeostasis and explain its importance for proper body
functions.
c. Relate in practice the knowledge of the etymology of anatomical and
physiological terms.
Introduction
Most of us are naturally curious about or bodies; we want to know what
makes us alive and why do we get sick. Infants can keep themselves happy for a
long time by just staring at their hands or pulling their mother’s nose. Older
children wonder where the food goes after they swallow or even wonder or
rather believe that they would grow a watermelon inside their belly once they
swallow its seed. Adults become upset when their hearts pound, when they
have uncontrollable hit flashes, or when they cannot keep their weight down.
Anatomy and physiology, subdivisions of biology, explore many of these
topics as they describe how our bodies are put together and how they work.
An Overview of Anatomy and Physiology
Anatomy – is the study of the structure and shape of the body and its parts and
their relationship to one another.
Greek word: tomy – to cut; ana - apart
Subdivisions:
Gross anatomy – looking at our own body or study large body structures such as
heart and bones; that is, we are studying large, easily observable structures.
Microscopic anatomy - the study of body structures that are too small to be seen
with the naked eye. The cells and tissues of the body can only be seen through
a microscope.
Physiology – is the study of how the body and its parts work or function;
physio = nature, ology = the study of.
C. M. D. Hamo-ay
, 1 Anatomy and Physiology
2
Levels of Structural Organization
Six Levels:
1. Chemical level – simplest level of the structural ladder. At this level,
atoms, tiny building blocks of matter, combine to form molecules such
as water, sugar, and proteins, like those that make up our muscles.
2. Cellular level - molecules, in turn, associate in specific ways to form
microscopic cells, the smallest unit of all living things.
3. Tissue level – Tissues consist of groups similar cells that have a
common function.
4. Organ level – an organ is a structure composed of two or more tissue
types that performs a specific function for the body.
5. Organ system level – an organ system is a group of organs that
work together to accomplish a common purpose. For example, the
heart and blood vessels of the cardiovascular system circulate blood
continuously to carry nutrients and oxygen to all body cells. An organ
systems make up the living human being.
6. Organism – represents the highest level of structural organization.
The organismal level is the sum total of all structural levels working
together to keep us alive.
Maintaining Life
Necessary Life Functions
1. Maintaining Boundaries – every living organism must be able to
maintain its boundaries so that its “inside: remains distinct from its
“outside”. Every cell of the human body is surrounded by an external
membrane that separates its contents from the outside interstitial fluid
(fluid between cells) and allows entry of needed substances. The body as
a whole is also enclosed by the integumentary system, or skin. The
integumentary system protects internal organs from drying out, from
pathogens, and from the damaging effects of heat, sunlight, and
unbelievable number of chemical substances in the external environment.
2. Movement – includes all the activities promoted by the muscular system,
such as propelling ourselves from one place to another (by walking,
swimming, and so forth) and manipulating the external environment with
our fingers. The skeletal system provides the bones that the muscles pull
on as they work. Movement also occurs when substances such as blood,
foodstuffs, and urine are propelled through the internal organs of the
cardiovascular systems, respectively.
C. M. D. Hamo-ay
, 1 Anatomy and Physiology
3
3. Responsiveness – or irritability, is the ability to sense changes
(stimuli) in the environment and then to react to them. For example, if you
accidentally touch a hot pan, you involuntarily pull your hand away from
the painful stimulus (the hot pan). You do not need to think about it—it
just happens. Because nerve cells are highly irritable and can
communicate rapidly with each other via electrical impulses, the nervous
system bears the major responsibility for responsiveness.
4. Digestion – is the process of breaking down ingested food into simple
molecules that can then be absorbed into the blood. The nutrient-rich
blood is then distributed to all body cells by the cardiovascular system,
where body cells use these simple molecules for energy and raw
materials.
5. Metabolism – is a broad term that refers to all chemical reactions that
occur within the body and all of its cells. It includes breaking down
complex substances into simpler building blocks, making larger structures
from smaller ones, and using adenosine triphosphate (ATP), the energy-
rich molecules that power cellular activities.
6. Excretion – is the process of removing excreta, or wastes, from the body.
Several organ systems participate in excretion. For example, the digestive
system rides the body of indigestible food residues in feces, the urinary
system disposes of nitrogen-containing metabolic wastes in urine, and the
skin disposes of various waste products as components of sweat.
7. Reproduction – the production of offspring, can occur on the cellular or
organismal level. Reproduction of the human organism is the task of the
organs of the reproductive system, which produce sperm and eggs. When
a sperm unites with an egg, a fertilized egg forms, which then develops
into a baby within the mother’s body. The function of the reproductive
system is regulated very precisely by hormones of the endocrine system.
8. Growth – can be an increase in cell size or an increase in body size that is
usually accomplished by an increase in the number of cells. For growth to
occur, cell-constructing activities must occur at a faster rate than cell-
destroying ones. Hormones released by the endocrine system play a
major role in directing growth.
Survival Needs
The goal of nearly all body systems is to maintain life. However, life is
extraordinarily fragile and requires that several factors be available. These
factors, which we will call survival needs include:
1. Nutrients – which the body takes in through food, contain the chemicals
used for energy and cell building. Carbohydrates are the major energy-
providing fuel for body cells. Proteins and, to lesser extent, fats are
C. M. D. Hamo-ay
, 1 Anatomy and Physiology
4
essential for building cell structures. Fats also cushion body organs and
provide reserve fuel. Minerals and vitamins are required for the chemical
reactions that go on in cells and for oxygen transport in the blood.
2. Oxygen – because the chemical reactions that release energy from foods
require oxygen, human cells can only survive for only a few minutes
without it. It is made available to the blood and body cells by the
cooperative efforts of the respiratory and cardiovascular systems.
3. Water – accounts for 60 to 80 percent of the body weight, depending on
the age of the individual. It is the single most abundant chemical
substance in the body and provides the fluid base for body secretions and
excretions. We obtain water chiefly from ingesting foods or liquids, and we
lose it by evaporation from the lungs and skin and in body excretions.
4. Normal Body Temperature – if chemical reactions are to continue at
life-sustaining levels, normal body temperature must be maintained. If
body temperature drops below 37 0C (98.60F), metabolic reactions
becomes slower and finally stop. If body temperature is too high, chemical
reactions proceed too rapidly, and body proteins begin to break down. At
either extreme, death occurs.
5. Atmospheric pressure – the force exerted on the surface of the body by
the weight of air. Breathing and the exchange of oxygen and carbon
dioxide in the lungs depend on appropriate atmospheric pressure. At high
altitudes, where the air is thin and atmospheric pressure is lower, gas
exchange may be too slow to support cellular metabolism.
The Language of Anatomy
Anatomical Position
To accurately describe body
parts and position, we must
have an initial reference
point and use directional
terms. To avoid confusion,
we always assume that the
body is in a standard
position called anatomical
position. In anatomical
position, the body is erect
with the feet parallel
and the arms hanging at
the sides with the palms
facing forward.
C. M. D. Hamo-ay
1
UNIT 1: ANATOMY
Intended Learning Outcomes
a. Define anatomy and physiology and explain their relationship.
b. Define homeostasis and explain its importance for proper body
functions.
c. Relate in practice the knowledge of the etymology of anatomical and
physiological terms.
Introduction
Most of us are naturally curious about or bodies; we want to know what
makes us alive and why do we get sick. Infants can keep themselves happy for a
long time by just staring at their hands or pulling their mother’s nose. Older
children wonder where the food goes after they swallow or even wonder or
rather believe that they would grow a watermelon inside their belly once they
swallow its seed. Adults become upset when their hearts pound, when they
have uncontrollable hit flashes, or when they cannot keep their weight down.
Anatomy and physiology, subdivisions of biology, explore many of these
topics as they describe how our bodies are put together and how they work.
An Overview of Anatomy and Physiology
Anatomy – is the study of the structure and shape of the body and its parts and
their relationship to one another.
Greek word: tomy – to cut; ana - apart
Subdivisions:
Gross anatomy – looking at our own body or study large body structures such as
heart and bones; that is, we are studying large, easily observable structures.
Microscopic anatomy - the study of body structures that are too small to be seen
with the naked eye. The cells and tissues of the body can only be seen through
a microscope.
Physiology – is the study of how the body and its parts work or function;
physio = nature, ology = the study of.
C. M. D. Hamo-ay
, 1 Anatomy and Physiology
2
Levels of Structural Organization
Six Levels:
1. Chemical level – simplest level of the structural ladder. At this level,
atoms, tiny building blocks of matter, combine to form molecules such
as water, sugar, and proteins, like those that make up our muscles.
2. Cellular level - molecules, in turn, associate in specific ways to form
microscopic cells, the smallest unit of all living things.
3. Tissue level – Tissues consist of groups similar cells that have a
common function.
4. Organ level – an organ is a structure composed of two or more tissue
types that performs a specific function for the body.
5. Organ system level – an organ system is a group of organs that
work together to accomplish a common purpose. For example, the
heart and blood vessels of the cardiovascular system circulate blood
continuously to carry nutrients and oxygen to all body cells. An organ
systems make up the living human being.
6. Organism – represents the highest level of structural organization.
The organismal level is the sum total of all structural levels working
together to keep us alive.
Maintaining Life
Necessary Life Functions
1. Maintaining Boundaries – every living organism must be able to
maintain its boundaries so that its “inside: remains distinct from its
“outside”. Every cell of the human body is surrounded by an external
membrane that separates its contents from the outside interstitial fluid
(fluid between cells) and allows entry of needed substances. The body as
a whole is also enclosed by the integumentary system, or skin. The
integumentary system protects internal organs from drying out, from
pathogens, and from the damaging effects of heat, sunlight, and
unbelievable number of chemical substances in the external environment.
2. Movement – includes all the activities promoted by the muscular system,
such as propelling ourselves from one place to another (by walking,
swimming, and so forth) and manipulating the external environment with
our fingers. The skeletal system provides the bones that the muscles pull
on as they work. Movement also occurs when substances such as blood,
foodstuffs, and urine are propelled through the internal organs of the
cardiovascular systems, respectively.
C. M. D. Hamo-ay
, 1 Anatomy and Physiology
3
3. Responsiveness – or irritability, is the ability to sense changes
(stimuli) in the environment and then to react to them. For example, if you
accidentally touch a hot pan, you involuntarily pull your hand away from
the painful stimulus (the hot pan). You do not need to think about it—it
just happens. Because nerve cells are highly irritable and can
communicate rapidly with each other via electrical impulses, the nervous
system bears the major responsibility for responsiveness.
4. Digestion – is the process of breaking down ingested food into simple
molecules that can then be absorbed into the blood. The nutrient-rich
blood is then distributed to all body cells by the cardiovascular system,
where body cells use these simple molecules for energy and raw
materials.
5. Metabolism – is a broad term that refers to all chemical reactions that
occur within the body and all of its cells. It includes breaking down
complex substances into simpler building blocks, making larger structures
from smaller ones, and using adenosine triphosphate (ATP), the energy-
rich molecules that power cellular activities.
6. Excretion – is the process of removing excreta, or wastes, from the body.
Several organ systems participate in excretion. For example, the digestive
system rides the body of indigestible food residues in feces, the urinary
system disposes of nitrogen-containing metabolic wastes in urine, and the
skin disposes of various waste products as components of sweat.
7. Reproduction – the production of offspring, can occur on the cellular or
organismal level. Reproduction of the human organism is the task of the
organs of the reproductive system, which produce sperm and eggs. When
a sperm unites with an egg, a fertilized egg forms, which then develops
into a baby within the mother’s body. The function of the reproductive
system is regulated very precisely by hormones of the endocrine system.
8. Growth – can be an increase in cell size or an increase in body size that is
usually accomplished by an increase in the number of cells. For growth to
occur, cell-constructing activities must occur at a faster rate than cell-
destroying ones. Hormones released by the endocrine system play a
major role in directing growth.
Survival Needs
The goal of nearly all body systems is to maintain life. However, life is
extraordinarily fragile and requires that several factors be available. These
factors, which we will call survival needs include:
1. Nutrients – which the body takes in through food, contain the chemicals
used for energy and cell building. Carbohydrates are the major energy-
providing fuel for body cells. Proteins and, to lesser extent, fats are
C. M. D. Hamo-ay
, 1 Anatomy and Physiology
4
essential for building cell structures. Fats also cushion body organs and
provide reserve fuel. Minerals and vitamins are required for the chemical
reactions that go on in cells and for oxygen transport in the blood.
2. Oxygen – because the chemical reactions that release energy from foods
require oxygen, human cells can only survive for only a few minutes
without it. It is made available to the blood and body cells by the
cooperative efforts of the respiratory and cardiovascular systems.
3. Water – accounts for 60 to 80 percent of the body weight, depending on
the age of the individual. It is the single most abundant chemical
substance in the body and provides the fluid base for body secretions and
excretions. We obtain water chiefly from ingesting foods or liquids, and we
lose it by evaporation from the lungs and skin and in body excretions.
4. Normal Body Temperature – if chemical reactions are to continue at
life-sustaining levels, normal body temperature must be maintained. If
body temperature drops below 37 0C (98.60F), metabolic reactions
becomes slower and finally stop. If body temperature is too high, chemical
reactions proceed too rapidly, and body proteins begin to break down. At
either extreme, death occurs.
5. Atmospheric pressure – the force exerted on the surface of the body by
the weight of air. Breathing and the exchange of oxygen and carbon
dioxide in the lungs depend on appropriate atmospheric pressure. At high
altitudes, where the air is thin and atmospheric pressure is lower, gas
exchange may be too slow to support cellular metabolism.
The Language of Anatomy
Anatomical Position
To accurately describe body
parts and position, we must
have an initial reference
point and use directional
terms. To avoid confusion,
we always assume that the
body is in a standard
position called anatomical
position. In anatomical
position, the body is erect
with the feet parallel
and the arms hanging at
the sides with the palms
facing forward.
C. M. D. Hamo-ay
