ॐ Human Physiology 卐
What is Physiology?
Physiology is the study of the characteristics and mechanisms of the human
body.
Cells are the basic unit of life and approximately 100 trillion cells make up the
typical human, each specially adapted to perform one or a few particular
functions. Nearly 25 trillion red blood cells function by transporting oxygen
from the lungs to all tissues in the body. All cells have some basic
commonalities. Oxygen reacts with carbohydrates, fat, and protein to release
energy, nutrient consumption, and energy production mechanisms. Almost all
cells have the ability to reproduce further similar cells.
Human Physiology
The major systems of the human body are as follows:
• The Endocrine System
,The endocrine system is an integration system influencing the metabolic
activities of cells. It functions through hormones – chemical messengers
synthesized by endocrine glands namely – hypothalamus, pineal, pituitary,
parathyroid, thyroid, gonads, and adrenals.
Hormones – They are the chemical substances produced by the endocrine
glands that control the metabolic functions of other cells.
1. Steroid based hormones – cholesterol derivatives.
2. Amino acid-based hormones: single modified amino acids, amino acid
derivatives, proteins, peptides, glycoproteins.
3. Eicosanoids — derivatives of arachidonic acid, 20-carbon polyunsaturated fatty
acid
Mechanisms of Hormone Action
Synthesised hormones affect on target cells by:
, Changing in membrane permeability as a result of the closing and opening of
the channels.
Deactivation or activation of regulatory molecules — covalent modification.
Synthesis of regulatory molecules involves changes in gene expression. All
these effects result in physiological changes, including :
1. Mitotic stimulation
2. Contraction or relaxation
3. Induction of secretory activity.
• The Nervous System
The nervous system is a complex network of nerves and cells that perform
three overlying functions of sensory input, integration, and motor output. This
process is generally the same even at a very primitive level of the nervous
system.
1. The sensory input is sensing the environment and changes in an organism and is
carried out by sensory organs like eyes, ears, nose, tongue, and skin, some of them
performing simultaneously.
What is Physiology?
Physiology is the study of the characteristics and mechanisms of the human
body.
Cells are the basic unit of life and approximately 100 trillion cells make up the
typical human, each specially adapted to perform one or a few particular
functions. Nearly 25 trillion red blood cells function by transporting oxygen
from the lungs to all tissues in the body. All cells have some basic
commonalities. Oxygen reacts with carbohydrates, fat, and protein to release
energy, nutrient consumption, and energy production mechanisms. Almost all
cells have the ability to reproduce further similar cells.
Human Physiology
The major systems of the human body are as follows:
• The Endocrine System
,The endocrine system is an integration system influencing the metabolic
activities of cells. It functions through hormones – chemical messengers
synthesized by endocrine glands namely – hypothalamus, pineal, pituitary,
parathyroid, thyroid, gonads, and adrenals.
Hormones – They are the chemical substances produced by the endocrine
glands that control the metabolic functions of other cells.
1. Steroid based hormones – cholesterol derivatives.
2. Amino acid-based hormones: single modified amino acids, amino acid
derivatives, proteins, peptides, glycoproteins.
3. Eicosanoids — derivatives of arachidonic acid, 20-carbon polyunsaturated fatty
acid
Mechanisms of Hormone Action
Synthesised hormones affect on target cells by:
, Changing in membrane permeability as a result of the closing and opening of
the channels.
Deactivation or activation of regulatory molecules — covalent modification.
Synthesis of regulatory molecules involves changes in gene expression. All
these effects result in physiological changes, including :
1. Mitotic stimulation
2. Contraction or relaxation
3. Induction of secretory activity.
• The Nervous System
The nervous system is a complex network of nerves and cells that perform
three overlying functions of sensory input, integration, and motor output. This
process is generally the same even at a very primitive level of the nervous
system.
1. The sensory input is sensing the environment and changes in an organism and is
carried out by sensory organs like eyes, ears, nose, tongue, and skin, some of them
performing simultaneously.
