The cell was first discovered and named by Robert Hooke in 1665. He remarked that it looked strangely similar to cellula or small rooms which monks inhabited, thus deriving the name. However what Hooke actually saw was the dead cell walls of plant cells (cork) as it appeared under the microscope. surface Anatomy: The study of anatomical landmarks that can be identified by observing the surface of the body. Sometimes called superficial anatomy. microscopic anatomy: The study of minute anatomical structures on a microscopic scale, including cells (cytology) and tissues (histology). Gross (or macroscopic) anatomy: The study of anatomical features visible to the naked eye, such as internal organs and external features. embryology: The science of the development of an embryo from the fertilization of the ovum to the fetal stage. dissection: The process of disassembling an organism to determine its internal structure and understand the functions and relationships of its components. surface Anatomy: The study of anatomical landmarks that can be identified by observing the surface of the body. Sometimes called superficial anatomy. microscopic anatomy: The study of minute anatomical structures on a microscopic scale, including cells (cytology) and tissues (histology). Gross (or macroscopic) anatomy: The study of anatomical features visible to the naked eye, such as internal organs and external features. embryology: The science of the development of an embryo from the fertilization of the ovum to the fetal stage. dissection: The process of disassembling an organism to determine its internal structure and understand the functions and relationships of its components.

1. Introduction
To Human Anatomy and Physiology
Presented by : Jagruti Marathe

2. Unit I 10 hours
 Introduction to human body
 Definition and scope of anatomy and physiology,
 levels of structural organization and body systems,
 basic life processes,
 homeostasis,
 basic anatomical terminology.

3. Introduction to human body
History
• The cell was first discovered and named by Robert Hooke in 1665.
• He remarked that it looked strangely similar to cellula or small
rooms which monks inhabited, thus deriving the name. However
what Hooke actually saw was the dead cell walls of plant cells
(cork) as it appeared under the microscope.
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4. Introduction to human body
Anatomy
• Anatomy is the branch of biology concerned with the study of the structure
of organisms and their parts.
• Anatomy is a branch of natural science which deals with the structural
organization of living things. It is an old science, having its beginnings in
prehistoric times.
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5. Introduction to human body
Anatomy
• surface Anatomy: The study of anatomical landmarks that can be identified
by observing the surface of the body. Sometimes called superficial
anatomy.
• microscopic anatomy: The study of minute anatomical structures on a
microscopic scale, including cells (cytology) and tissues (histology).
• Gross (or macroscopic) anatomy: The study of anatomical features visible
to the naked eye, such as internal organs and external features.
• embryology: The science of the development of an embryo from the
fertilization of the ovum to the fetal stage.
• dissection: The process of disassembling an organism to determine its
internal structure and understand the functions and relationships of its
components.
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6. Introduction to human body
Physiology
• Human physiology is the study of the mechanical, physical, and
biochemical processes that support the body’s function.
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7. Introduction to human body
 levels of stru c tu ral organ ization an d b od y systems
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Atom Molecule Organelles Cell Tissues Organ
Organ
System

8. Introduction to human body
 h omeostasis,
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Receptor
Control
Center
Effector

9. Introduction to human body
 h omeostasis,
• Homeostasis is the maintenance of the body’s overall inner resistance to
change.
• This resistance stabilizes the body by regulating the internal environment,
even as the external environment changes.
• A stable internal environment is needed for normal physiological function
and survival of a living system.
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10. Introduction to human body
 h omeostasis,
• Maintaining a stable internal environment requires constant
monitoring, mostly by the brain and nervous system.
• The brain, more specifically the hypothalamus, receives information
from the body and responds appropriately through the release of
chemical messengers such as neurotransmitters, catecholamines,
and hormones.
• These chemical messengers signal individual organs to change their
functions in order to maintain homeostasis for the whole body.
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11.  Homeostasis( Feed b ac k Mec h an ism)
Feedback Mechanism Types :
• There are two types of feedback mechanisms, depending on whether the input
changes or the physiological parameters deviate from their limits.
• Although the reactions of various processes to changes in variables varied, the
loop’s components are similar.
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Positive Negative

12. I. Positive feedback mechanism
• A positive feedback mechanism involves more stimulation or the acceleration of
the process.
Positive feedback mechanism definition
• As the name implies, a positive feedback mechanism or positive feedback
homeostasis is a pathway that, in response to an output variation, causes the
output to vary even more in the direction of the initial deviation.
• A positive feedback system amplifies deviations and causes output state changes.
Because it moves the body away from homeostasis, positive feedback mechanisms
are significantly less common than negative feedback mechanisms.
• As long as the stimulus (example: the presence of the stimulant) is maintained, the
positive feedback system gradually increases the reaction.
• A single component that activates its own activity or numerous components with
direct and indirect interactions might make up a positive feedback loop.
• Positive feedback loops in biological processes are common in processes that need
to happen fast and efficiently, as the output tends to magnify the stimulus’
influence.
• Positive mechanisms are rare in living systems such as the human body, but they
can be found in the environment, such as in the instance of fruit ripening
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Positive Negative

13. • Steps / Process / Mechanism of positive feedback mechanism
• The process of a positive feedback loop consists of a control system that consists of various
components, working in a circular pathway to stimulate or inhibit one another. The overall process
can be described in terms of the components of the system.
1. Stimulation. The stimulation that initiates the positive feedback loop in order to complete a process
is the initial step. Hormones released by various organs as a result of the start of a process are the
most common stimuli in the human body.
2. Reception. The second step in the loop is the reception of stimuli via various sensors, which provide
data to the control unit. These receptors are mostly nerves that transmit signals from the stimulus
location to the control unit, which is the brain in humans.
3. Processing. The processing of information supplied to the control unit by the receptors is the next
phase in the loop. The control unit tallies the data and displays an output if the stimulus is outside
the typical range of the value.
4. Stimuli are activated even more. In order to induce an output in response to the stimulus,
information from the brain is conveyed to the location of action via several nerves. The brain’s
messages tend to activate the stimulus even more in the direction of deviation in the case of a
positive feedback loop.
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Blood Clotting
Child Birth
Menstruation Cycle

15. • Negative feedback mechanism definition
• A negative feedback mechanism, often known as negative feedback homeostasis, is a pathway that is
triggered by a deviation in output and produces changes in output in the opposite direction of the
initial deviation.
• After the control unit analyzes the magnitude of the deviation, the negative feedback mechanism
drives the variable factors towards a stable state or homeostasis.
• Positive feedback loops are less prevalent than negative feedback loops because negative feedback
loops tend to stabilize the system.
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17. • Steps in a negative feedback mechanism
• The negative feedback system works in a similar way to the positive feedback loop in that it is
activated by stimuli and eventually leads to modifications that tend to cancel out those impulses.
The following is a summary of the overall procedure:
1. Stimulation. The development of stimuli as a result of physiological parameter deviations from the
normal value is the initial stage in the negative feedback loop. Physiological parameters can deviate
from the norm in either direction.
2. Reception. The control unit receives changes in physiological parameters through a variety of
located throughout the body. Nerves and other thermoreceptors are examples of common receptors
engaged in stimulus transmission.
3. Processing. The brain serves as the loop’s control unit, determining whether a change in a
parameter necessitates loop activation or inhibition. The brain sends out signals to erase the
alterations in different ways depending on the direction of departure.
4. Counteract on the stimulus. The control unit sends out signals at the end of the loop to cancel out
impacts that cause changes in physiological variables. Changes can take several forms and be
directed at different sections of the body.
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18. • Regulating Temperature
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22. Thank You