BIO181, Anatomy & Physiology I
or
Everything you always wanted to know
about Human Anatomy & Physiology*
(*but were afraid to ask)
Prologue, part I
Introduction to Anatomy & Physiology
Dr. Patricio Mujica
PART 1
OVERVIEW OF ANATOMY AND
PHYSIOLOGY
© 2016 Pearson Education, Inc.
WHAT ARE ANATOMY
AND
PHYSIOLOGY?
• Science is a collection of methods of observing and measuring
natural phenomena
▪ Allows us to explain these phenomena, make predictions about
reality, and test those predictions using experimental approaches
▪ The Scientific Method summarizes how science is done
• Scientific inquiry over the last 150 years has led to tremendous
advances in our understanding of human body and how it
functions.
• Form and function are inextricably linked
▪ Human Anatomy – study of structure or form of human body
▪ Human Physiology – study of body’s functions
CHARACTERISTICS
OF
LIVING ORGANISMS
• Cellular composition
▪ Smallest unit that can carry out functions of life
▪ All organisms are composed of cells
• Metabolism – collection of chemical reactions happening in a cell
▪ Metabolic processes either build up or break down substances depending on needs of
organism
• Growth, by increase in size or number of cells
• Excretion – elimination of potentially harmful waste products
• Responsiveness or irritability – organisms sense and react to stimuli or
changes in their environment
• Movement – by an entire organism, or by individual cells within an organism
• Reproduction – takes two forms in multicellular organisms:
▪ Individual cells reproduce within organism; serves the purpose of growth but also
useful to replace damaged or old cells
▪ Organism itself reproduces to yield similar offspring
LEVELS OF STRUCTURAL ORGANIZATION
THE HUMAN BODY HAS 11 ORGAN SYSTEMS
•
Body’s organs are grouped into 11 organ systems
consist of two or more organs that together carry out
a broad function in body
▪ Organs and organ systems work together to ensure
survival of organism as a whole
•
Organ systems function together to make up
complete organism (human body)
THE HUMAN BODY HAS 11 ORGAN SYSTEMS
IN DEPTH IN THE FIRST SEM ESTER OF A&P
STUDIED
IN DEPTH IN THE FIRST SEM ESTER OF A&P
THE HUMAN BODY HAS 11 ORGAN SYSTEMS
STUDIED
THE HUMAN BODY HAS 11 ORGAN SYSTEMS
IN DEPTH IN THE SECOND SEM ESTER OF A&P
STUDIED
IN DEPTH IN THE SECOND SEM ESTER OF A&P
THE HUMAN BODY HAS 11 ORGAN SYSTEMS
STUDIED
THE HUMAN BODY HAS 11 ORGAN SYSTEMS
STUDIED
IN DEPTH IN THE SECOND SEM ESTER OF A&P
PART 2
THE LANGUAGE OF
ANATOMY AND PHYSIOLOGY
© 2016 Pearson Education, Inc.
ANATOMICAL TERMINOLOGY
• Medical professionals speak a common language that every
practitioner understands when referring to the human body.
Arm X-ray
but which arm?
Abdominal CT scan
but where is the stomach?
Coronary angiography
but what side of the heart?
• A set of specific terms and rules are used to ensure efficient and accurate communication
in the medical environment
EVERYONE IN A HEALTHCARE TEAM NEEDS TO KNOW WHAT THEY’RE LOOKING AT!
ANATOMICAL POSITION
•
Common frame of reference across the
entire medical and healthcare community
•
Used to describe all body parts and regions
▪ standing upright
▪ feet are shoulder width apart
▪ upper limbs at sides of trunk and head
▪ palms facing forward
•
Body is always referred to as if it were in
anatomical position, even when it’s in another
position
•
“Right” and “left” always refers to right and
left sides of body being described, never our
own
Right side
Left side
DIRECTIONAL TERMS
• Paired terms that describe the relative location of body
parts and markings
▪ Anterior (ventral) refers to front
Posterior (dorsal) refers to back
o
can refer to either body as a whole or to a body part
▪ Superior (cranial) means toward head
Inferior (caudal) refers to toward tail/tailbone
o
terms are used to refer to positions only on head,
neck, and trunk
▪ Proximal is closer to point of origin
Distal is more distant or further away from
same point of origin
▪ Superficial structures are closer to surface of the
body;
Deep structures refers to those further away
• The body’s midline is an imaginary line that
runs down middle of the body
▪ Medial refers to a position that is closer to midline;
Lateral refers to a position that is further away from it
REGIONAL TERMS
• Body can be divided into two regions:
▪ axial region – head, neck, and trunk
▪ appendicular region – upper and lower limbs
• Each broad region can be divided into several smaller regions
REGIONAL TERMS
• Body can be divided into two regions:
▪ axial region – head, neck, and trunk
▪ appendicular region – upper and lower limbs
• Each broad region can be divided into several smaller regions
PLANES OF SECTION
Provide a means of studying a body region or part by dividing it up
for examination. Three main planes, with their variations:
•
Sagittal plane divides body or body part into right and left
sections
• Frontal plane (coronal plane) divides body or body part into
anterior and posterior sections
• Transverse plane (horizontal plane) divides body or body part
into:
▪ superior and inferior sections of the axial region, or
▪ proximal and distal sections of the appendicular region
PLANES OF SECTION
Provide a means of studying a body region or part by dividing it up
for examination. Three main planes, with their variations:
•
Sagittal plane divides body or body part into right and left
sections
▪ Midsagittal plane
(median plane) divides
body or body part into
equal left and right sections
▪ Parasagittal plane divides
body or body part into
unequal right and left sections
PLANES OF SECTION
Provide a means of studying a body region or part by dividing it up
for examination. Three main planes, with their variations:
•
Frontal plane (coronal plane) divides body or body part into
anterior and posterior sections
PLANES OF SECTION
Provide a means of studying a body region or part by dividing it up
for examination. Three main planes, with their variations:
•
Transverse plane (horizontal plane) divides body or body part
into:
▪ superior and inferior
sections of the
axial region, or
▪ proximal and distal
sections of the
appendicular region
PART 3
ORGANIZATION OF THE
HUMAN BODY
© 2016 Pearson Education, Inc.
BODY CAVITIES
•
A cavity is any fluid-filled space within the body
▪ axial region of body is divided into several cavities
•
•
Protect internal organs
Allow organs to move and expand
▪ necessary to perform their functions
•
Major cavities include dorsal and ventral cavities
and their subdivisions
© 2016 Pearson Education, Inc.
BODY CAVITIES
Dorsal cavity
•
•
•
Protects the central nervous system
•
(brain and spinal cord)
Surrounded by skull and vertebrae
•
Filled with cerebrospinal fluid (CSF)
Ventral cavity
Two major divisions: thoracic and abdominopelvic
cavities, separated by diaphragm muscle
Majority of organs within these divisions are surrounded
by serous membranes that create fluid-filled subcavities
Surround and protect
lungs; one pleura per
lung, cavity is fluid-filled
In between pleural
cavities; location of
heart, trachea, esophagus.
Created by a serous membrane that surrounds heart
Houses the peritoneum, a
serous membrane that
surrounds several organs
within the peritoneal
cavity
BODY CAVITIES
Ventral cavity
•
Abdominopelvic cavity can be
divided up into four quadrants by
drawing two imaginary lines that
cross at umbilicus
•
Two major divisions: thoracic and abdominopelvic
cavities, separated by diaphragm muscle
Majority of organs within these divisions are surrounded
by serous membranes that create fluid-filled subcavities
Surround and protect
lungs; one pleura per
lung, cavity is fluid-filled
In between pleural
cavities; location of
heart, trachea, esophagus.
Created by a serous membrane that surrounds heart
Houses the peritoneum, a
serous membrane that
surrounds several organs
within the peritoneal
cavity
BODY CAVITIES
Ventral cavity
•
Abdominopelvic cavity can also be
divided up into a grid of nine
segments by two parasagittal and
two transverse imaginary lines
•
Two major divisions: thoracic and abdominopelvic
cavities, separated by diaphragm muscle
Majority of organs within these divisions are surrounded
by serous membranes that create fluid-filled subcavities
Surround and protect
lungs; one pleura per
lung, cavity is fluid-filled
In between pleural
cavities; location of
heart, trachea, esophagus.
Created by a serous membrane that surrounds heart
Houses the peritoneum, a
serous membrane that
surrounds several organs
within the peritoneal
cavity
SEROUS MEMBRANES
• Thin sheets of tissue that surround heart, lungs, and many abdominal organs
• Consist of a single, continuous layer of tissue that folds over itself to create a
double-layered structure, which gives appearance of two separate membranes
▪ Visceral layer – in contact with underlying organ
▪ Parietal layer – outermost layer attached to surrounding structures
• Cavity between two layers is filled with an extremely thin layer of fluid
called serous fluid
o
Watery, slippery lubricant made by cells of membrane
o
Fills space between membrane layers
o
Prevents friction caused by movement of organs
PART 4
CORE PRINCIPLES IN ANATOMY
AND PHYSIOLOGY
© 2016 Pearson Education, Inc.
HOMEOSTASIS
IS A
STATE
OF
BALANCE
Homeostasis is defined as the
dynamic maintenance of the
body’s regulated physiological
variables, despite changes in the
external or internal environments.
HOMEOSTASIS
IS A
STATE
OF
BALANCE
These are examples of
homeostatic imbalances
Homeostasis is defined as the
dynamic maintenance of the
body’s regulated physiological
variables, despite changes in the
external or internal environments.
HOMEOSTASIS
IS A
STATE
OF
BALANCE
feedback
mechanisms
response
mechanisms
These are examples of
homeostatic imbalances
sensing mechanisms
processing or
integrating
mechanisms
HOMEOSTASIS
IS A
STATE
OF
BALANCE
feedback
mechanisms
response
mechanisms
sensing mechanisms
The regulated variable is
constantly monitored by the
sensing mechanisms
Sensory information is constantly
fed to the integrating mechanisms
processing or
integrating
mechanisms
The body can then quickly respond to new imbalances by
turning on the response and feedback mechanisms
ALMOST EVERY MEANINGFUL HEALTH PARAMETER IS A
REGULATED PHYSIOLOGICAL VARIABLE
feedback
mechanisms
response
mechanisms
sensing mechanisms
Chemical composition of body fluids
- glucose concentration
- hormone concentration
- electrolyte concentration (Na+, K+, Ca2+, HCO3–, Cl–)
- partial pressure of gases (O2, CO2)
processing or
integrating
mechanisms
Resting blood pressure
Water content of body fluids
Rate of cell division
Activity of immune system
HOMEOSTASIS
•
IS
NOT A STATE
OF
EQUILIBRIUM
The healthy human body works hard to maintain all its regulated variables constantly
within a narrow physiological (or normal) range
Core body temperature
Resting blood pressure
Blood glucose concentration
Blood Na+ concentration
Blood K+ concentration
Blood Ca2+ concentration
Blood HCO3– concentration
Partial pressure of O2 (arterial blood)
Partial pressure of CO2 (arterial blood)
97-99 F (36-37 ºC)
Males: 115-120/70-80 mmHg; Females: 110-115/65-75 mmHg (Sys/Dia) (18-39yo)
70-100 mg/dL (fasting)
135-145 mmol/L
3.5-5.0 mmol/L
1.0-2.0 mmol/L
22-30 mmol/L
80-100 mmHg (at sea level)
35-45 mmHg (at sea level)
•
All of these values are markedly different from those you would find in the body’s
external environment, and represent a state of disequilibrium
•
Homeostatic imbalances usually occur when these values stray away from their
normal range, causing disease
▪
•
The body expends significant amounts of energy in maintaining this disequilibrium, and in
correcting imbalances caused by disease
A state of equilibrium between the body and its environment would mean that all
values would be equal
▪
This situation only occurs upon death, when the body can no longer produce the energy
required to regulate its internal composition.
CORE PRINCIPLES
IN
A&P
Concepts of anatomy and physiology related to
maintenance of homeostasis that you will see repeated
throughout every unit:
• Feedback loops
• Relationship between structure and function
• Gradients
• Cell-to-cell communication
FEEDBACK LOOPS
• General mechanism in which a change in a regulated variable is sensed and
•
processed, followed by a response that alters the regulated variable itself.
All feedback loops consist of a series of elements that mediate the flow of
information:
▪ Stimulus, which triggers a change in the regulated variable
▪ Receptor, which monitors the regulated variable and responds to changes in it
▪ Control Center, which integrates the signal from the receptor and produces a signal
that
▪ Effector, which receives the signal from the control center and triggers a response
that will directly affect the regulated variable
▪ Response, which is the change in the regulated variable due to the signal from the
effector
• Two types of feedback loop:
▪ Positive feedback loop
▪ Negative feedback loop
• The words positive and negative refer to the effect of the loop on the response.
POSITIVE FEEDBACK LOOPS
• Less common than negative feedback loops
• Effector activity increases and reinforces the response to stimulus
• Works by amplifying the effect of
the initial response
Response is terminated when the
regulated variable reaches an end-point
•
• Examples:
▪ Platelet activation in response
to vessel injury during blood
clotting
▪ Oxytocin release during childbirth
in response to cervix dilation
NEGATIVE FEEDBACK LOOPS
Most common form of regulation
•
Regulated variables are maintained close to
a predetermined set point
▪
they may vary around it within their
normal range.
•
•
A stimulus causes a deviation in the regulated variable away from its normal range
•
Effectors produce a response that returns the variable to its normal range
The receptor senses this change and signals to the control center, which in turn
recruits one or more effector cell type or organ
▪
•
The negative here refers to the fact that the effect of the stimulus is counteracted by the
loop
Once the variable is
back within normal range
the receptor no longer
signals and the feedback
loop is turned off
deviation from
normal range
stimulus
response: variable
returns to normal range
Feedback loop is turned off
once normal range is reached
CORE BODY TEMPERATURE IS REGULATED
BY NEGATIVE FEEDBACK LOOPS
STRUCTURE-FUNCTION RELATIONSHIPS
• One of most basic principles in A&P
•
Known as principle of complementarity of structure and function:
▪ Form of a structure is always such that it best suits its function
▪ States simply that form follows function; applies to each level of
organization even down to chemical level
GRADIENTS
•
A gradient exists when there is more of something in one area
compared to another
higher
lower
temperature
pressure
concentration
•
Gradients drive many physiological processes (respiration,
nutrient exchange, formation of urine—to name a few)
GRADIENTS
•
Examples of gradients found in our daily lives:
temperature
concentration
pressure
CELLULAR COMMUNICATION
• All bodily functions are carried out by cells and tissues within organs and organ
systems
▪ Maintenance of whole-body homeostasis requires that the function and activity of
these structures be coordinated
• Coordination is accomplished via chemical or electrical signals sent between
cells, either directly or across bodily fluids
▪ Electrical signals require direct physical
communication between neighboring cells
▪ Chemical signals can affect neighboring cells
or travel long distances through the blood and
trigger responses in tissues far away