BIOM 515 – HUMAN PHYSIOLOGY
Introduction to Human Physiology
Human Physiology is the process by which people live and work together with other
people, especially the mechanism that enables humans to live, work and interact in the
community. This branch of biology deals with the way that organs, organ systems, tissues, cells
and bio-molecules undertake the chemical and physical processes which underpin existence.
Physiology is basic in the sense that it gives an overview of how the human body functions
without abnormalities and how it reacts to diseases or excesses in certain components.
Significance of Human Physiology
Understanding Normal Body Function: Physiology is useful for knowing how this or that
organ or some bodies systems should function in the rightful way. Any body that has an interest
especially in the medical field should understand it since it is a foundation on which most
diseases are based and their handling.
1) Medical Advancements: The knowledge of anatomy is essential as the foundation for
developing the new ways of developing and curing the illnesses and improving people’s
lives by inventing progressive drugs and devices. It enables the researcher to record
impact of a number of intercessions with respect to system.
2) Health and Disease Management: Awareness of the internal procedures can contribute to
researches of interventions for chronic illnesses, enhance the outcomes of surgery, and
foster prevention-based models of care.
3) Enhancing Physical Performance: In this field knowledge from physiology is used in the
adjustment to the performances of athletes and regulating of their fitness for aid in the
creation of training schedules and feeding plans.
4) Adaptation and Survival: That knowledge is relevant especially for preparing and
effectively carrying out endeavours with exposure to some more harsh conditions such as
in the mountain, in the sea, and extraterrestrial environment that sometimes should won
by amount of physiological knowledge to be safe and efficient.
Cellular Physiology
This is a fact that can be considered rather awe-inspiring – every form of life possesses a
cell as its basic component and each cell, in its turn, controls dozens of biological processes.
Cellular physiology may be defined as a knowledge or perception of the manner and proportion
in which various occurrences take place in a cell and these include incidence of metabolic,
communication as well as transport events. Cell metabolism – collectively known as the sum
total of chemical transformations take place in cells; contain cellular respiration that is the
process of energy formation in cells in form of Adenosine Triphosphate (ATP). Also,
intercellular communication occurs through the use of molecules in wholesaling
neurotrasmissioners and hormones that coordinate cellular activities. Passive and active
transport are some of the movement procedures that assists transport of ions, molecules and other
particles across the cell membranes to enable cells to be fully functional as well as balancing all
the surroundings.
Homeostasis
One of the major functions in the human body is Homeostasis which is defined as the
process of maintaining a stable condition of the human body despite changes which may be
witnessed outside the body. Some of them that can be taken as examples of this dynamic
equilibrium are development of temperature symphony, pH level regulation and blood sugar
level maintenance. Cells, organs, and tissues which need to be regulated require feedback
mechanisms such as negative and positive feedback systems. Negative feedback mechanisms:
act in an opposite manner to eliminate the variation from the normal values Reversing feedbacks:
make the deviation worse often indicating some physiological activity. Together, they make it
possible to maintain constancy and possible some degree of buffering the complexities of the
internal environment in order to create a perfect ‘platform’ for the body to operate optimally in
the device.
Physiological Mechanisms Involved in Homeostasis include:
Temperature Regulation: They observe that the temperature is slightly high above this
normal temperature and they respond since the skin and hypothalamus send signals to the
brain that the body is warm and this is evidenced by actions such as vasodilation of blood
vessels and sweating. Once the body set point of temperature is achieved, hypothalamus
receives the feedback signal and stop the process of causing a state that cools the body.
pH Balance: If the pH level of blood is low (meaning blood is more acidic), there are
more receptors known as the chemoreceptors in the brain stem to it and it invokes the
respiratory center to deepen breathing and increase CO 2 output to make the blood less
acidic. On the other hand, if the pH of the blood is high meaning that it is more than 7.
35, the respiratory system decreases its rate of breathing to enable it retain more CO2 to
create an optimal concentration of bicarbonate Ions and therefore bring down the pH
level.
Blood Sugar Regulation: The following are some of the ramifications of insulin
Generally, when there is the intake of foods such as starches, the levels of blood glucose
rise and this leads to the creation of insulin within the pancreas. It helps one or more
cells in the body to take up glucose, thus reducing the prevailing levels of glycosuria in
the blood plasma. Once this blood sugar level is achieved it secrete insulin is low or cut
off all together Once this blood sugar level is achieved it secretes insulin is low or cut off
all together. On the other hand, when the nutrients interchange is low, as in fasting, or
when concentration of glucose in blood is low, glucagon is synthesized or released by the
pancreas to reduce the concentration of glucose in the liver while increasing the blood
glucose concentration.
Nervous System
Nervous system is a control and reporting system of a body and together with the above
given functions it also includes the following: receive and take rapid control of any stimulus in
internal and external environment of the organism and the coordinated response. It mostly
includes the brain and spinal cord known as Central Nervous System, CNS and the other body
structures that are known as Peripheral Nervous System, PNS and is mainly with control of
sensations and regulation of muscle and thought. Neurons are the exit and enter of the nervous
system and they allow to transfer a specific message across the synapse. Includes CNS in this
system because it is in a position to process the sensory info as well as give the motor response
and is made of the brain in addition to the spinal cord. However, the PNS is distributed
throughout the body’s physique and transmits rich content signals to the CNS and performs the
motor function. To fashion the circumference of exchanged secrets, we contain billions of
neurons linking to organize the nervous system as a control and regulator of every imaginable
type of human activity.
V. Endocrine System
The co-ordination for the physiological processes occurs within the endocrinal system,
which works in concert with the nervous system and the hormones. It consists of hypothalamus,
pituitary gland, thyroid gland, adrenal gland, pancreas and gonads, it directs metabolism process,
growth process and development and sexual characteristics and response to stress. Chemical
messengers; are compounds formed in the endocrine cells, which are then carried through the
blood stream to the effector organs to cause a specific reaction. This type of glands is most
sensitive to feedback one since they ensure the correct degree of hormones in the body in order
to attain hormonal balance or homeostasis. The nature of endocrine disorders may indeed be
general and encompass a selection of function since this system is regarded as quite critical for
operation of the human body.
VI. Cardiovascular System
Cardiovascular is one of the outstanding system in the body; it is made up of the heart,
the blood vessels and blood which has the roles of carrying oxygen, nutrition and waste products
in the body. This is a hard smooth tissue lying transversely in the chest cavity just below the
lungs and plays the role of pumping blood in the arterio-venous circulation or loop of vessels.
The systolic and diastolic is the one that characterizes the cycle of a heart that controls the
contraction and relaxation of its chambers with a view of sustaining the blood circulation. It
maintains the appropriate perfusion of tissue and organs, functionally being controlled by the
ANS and hormones, and being the measure of pressure in the arteries. In addition, blood is
placed into four types: Including: the hemoglobin which is involved in transportation and
livelihood cells which include platelets, white and red blood cells and plasma which is the
medium forimmunity, blood clotting as well as food absorption.
VII. Respiratory System
This system involves in the continuous production of gametes and the provision of
structures that enhance the process of fertilization and feilization. In males, the reproductive
system is comprised of the testes where sperm production takes place, additional organs,
epididymis, vas deferens, seminal vesicle, and prostate gland which are involved in sperm
transportation and ejaculation. In female reproductive system there is the ovaries in which
oogenesis takes place, the fallopian tubes, uterus and vagina through which the ova are
transported, fertile and pregnant respectively. Another example of hormonal regulation involves
the hypothalamic-pituitary-gonadal interaction responsible for physiological events like puberty,
menstration and pregnancy. Conception challenges, hormonal disturbances, and infections such
as those of sexual transmitted nature affect reproductive health and fertility.
VIII. Digestive System
The digestive system is perhaps the most important component in the human body
bearing the responsibility of processing all ingested food items, releasing nutrients into the body
and expelling unwanted components out of the body. It consists of specific structures known as
organs of digestion: mouth, oesophagus, stomach, small and large intestines, liver, pancreas, and
gall bladder, all of which contribute one or the other function. In the oral cavity, humans perform
mechanical and chemical digestion to reduce the size of food particles. The stomach churns the
food to mixture it with gastric juices that continue the digestion process while the small intestine
helps in the absorption of the nutrients into the blood. Salamander’s various accessory organs
include liver which secretes digestive enzymes, pancreas and gall bladder which also secrete
enzymes and bicarbonate ions to assist in digestion of carbohydrates, proteins and fats as well as
absorption of nutrients. The large intestine is devoid of villi and transports water and electrolytes
out of the homogeneous mixture and forms feces for expulsion. Digestive coordination is
controlled by neuronal and humoral means to facilitate absorption activities and disposal of
metabolic residues.
IX. Renal System
Renal or the bodily system is primarily consist of kidnies and urinary structures and is
involved mainly in the control of water and electrolyte, metabolism of foods and waste products
and the maintenance of acid base balance. It is subdivided into nephron units and operates as a
filter for the blood; that is, the body’s wastes and/or any unwanted elements if found in the blood
will be eliminated, in contrast to specific nutrients and ions which will be carried back into
circulation. Lassitude is initiated in glomerulus, whereas reabsorption and secretion are implied
at the renal tubules. It involves the processes of concentrating wastes and water and then dispose
wastes through the ureters, bladder, and urethra. Though aldosterone, ADH, ANP, the renal
function is influenced in a very careful manner; the neural mechanisms are also involved. kidney
diseases, may lead to distorted electrophilic balance, fluid imbalance, and wrong disposal of
wastes; and therefore are real pathological risks.
X. Musculoskeletal System
The musculoskeletal system provides the body with its form and supports the body to
move and protect the organs. The musculoskeletal system is complex of bones, muscles, and
joints that co-function in the body to support posture and execute voluntary movements. Bones
are the complex body structure that is inflexible: they provide support and protect vital organs.
They also offer sites of hematopoiesis and storage for minerals. Muscles constituted of skeletal,
smooth, and cardiac muscle tissue bring about the movement by contractions to generate force.
These skeletal muscles, attached to bones by tendons, are responsible for voluntary movement.
Associated with the skeletal muscles and, it almost seems, invariably with joints where there is
some articulation of bones, there is always flexibility and movement. All these are worked with
synovial liquid and the service of connective tissues. The musculoskeletal system constantly
changes and remodels throughout life under mechanical stress, hormonal signals, and growth
factors, adapting to changing physiological demands.
XI. Reproductive System
XII. Integration of Systems
The result of the integrated actions of the various physiological systems is the
coordination that protects the internal and external stimuli of the body and sustains it in a state of
health and homeostasis. There are feedback mechanisms, which include negative or positive
feedback loops, that control physiological variables, including body temperature, blood pressure,
and hormone levels. This interaction between the organ systems through neural, hormonal, and
paracrine signaling makes rapid adjustments according to changing environmental conditions
and metabolic demands. For example, the sympathetic nervous system mobilizes resources to
prepare the body for stress by increasing the rate of the heart and respiration while directing the
flow of blood to the skeletal muscles. Hormonal signals likewise adjust metabolic processes,
along with growth and reproduction, to the adaptability and survival of the body. Knowledge of
the integrative nature of physiological systems is necessary to understand the mechanisms
underlying health and disease to guide therapeutic interventions.
The descriptions outline different topics in quite a detailed manner that would present a full-
fledged account of human physiology, that is, the structure, function, and regulation of major
organs in the body.
XIII. Conclusion
Developed from present-day molecular cell biology and neuroscience, human physiology
involves a diverse complex of intertwined systems regulating the human body. Microscopic
processes in cells as well as General integration of functions of organs and tissues, are studied in
physiology with the aim of understanding the dynamics of health and disease or adaptation to a
particular environment. It is important for a human body to maintain a balance within that makes
environment for the cells and the whole body portable so homeostasis is the act of physiological
regulation that keeps the conditions favorable within the body. These two systems are considered
as headquarters that are responsible for controlling reactions of the body to internal and external
factors through distinct signaling network. There is cooperation and independence of every organ
system in maintaining this homeostasis; for instance, the cardiovascular system delivers nutrients
and oxygen to all tissues of the body, and the renal system controls water and electrolyte balance.
Development of physiological systems ensures that there are coordinated and smooth changes in
the internal environment that responds to outer environment conditions for the efficiency of the
body organs. In dissecting the complexities of human physiology, we understand the normally
and pathophysiologic processes in the human body facilitating preventative and remedial
measures to enhance quality and longevity of life.
