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UNIT- 1
BASICS OF HUMAN BODY
natomy is the study of the structure and relationship between body parts. Examples:
- Cell biology: Study of cellular structure and functions.
- Histology: Study of microscopic structure of tissues.
- Gross anatomy: Structures that can be examined without using a microscope.
- Systemic anatomy: Structure of specific systems of the body such as the nervous or respiratory systems.
- Regional anatomy: Study of Specific regions of the body such as the head or chest. Physiology is the study of the function of body parts and the body as a whole. Examples:
- Neurophysiology: Study about the functional properties of nerve cells.
- Endocrinology: Study about the hormone release and their actions.
- Cardiovascular physiology: Study about the functions of heart and blood vessels.
- Immunology: Study about the immune system and functions of immune cells.
- Respiratory physiology: Study about the respiration physiology and functions of lungs.
- Renal physiology: Study about functions of the kidneys. Note: Similar Terms: Pathophysiology: It is the branch of science deals with the study of disease and their pathogenesis. Levels of Structural Organization and Body Systems To study the various aspects of human body, It is divided into various levels of organization. 1.Chemical level
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2.Cellular level 3.Tissue level 4.Organ syatem level 5.Organism level 1.Chemical level. This is very basic components of every living organisms which includes atoms, the smallest units of matter that participate in chemical reactions, and molecules, two or more atoms joined together. Example of certain atoms, such as carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), calcium (Ca), and sulfur (S), are essential for maintaining life. Two main molecules found in the body are deoxyribonucleic acid (DNA), the genetic material passed from generation to next generation and so on, and glucose, commonly known as blood sugar. 2.Cellular level. Molecules combine to form cells, the basic structural and functional units of an organism. Among the many kinds of cells in your body are - Blood cells, Muscle cells, Nerve cell etc. 3.Tissue level. Tissues are groups of cells and the materials surrounding them that work together to perform a particular function, i.e similar action. There are four basic types of tissue in your body: epithelial tissue, connective tissue, muscular tissue, and nervous tissue. 4.Organ level. At this level tissues are joined together to form organs which are structures that are composed of two or more different types of tissues; they have specific functions and usually have recognizable shapes.
- Example: The respiratory system, which helps in breathing and respiration. Its organs include the nose, nostrils, pharynx (throat), larynx. bronchii, lungs, alveoli etc.
- Sometimes an organ is part of more than one system. Example is pancreas which is part of both the digestive system and the hormone- producing endocrine system. 5.Organismal level. An organism, contains many organ systems together to perform basic processesses of life. Diagram:
3. Movement: It includes motion of the whole body, individual organs, single cells, and even tiny structures inside cells. - Example- The combined action of leg muscles helpes in moving your whole body from one place to another when you walk or run.Wound healing and cleaning of cell debris from the injured part is the unique type on movement in the body. 4. Growth: It is an increase in body size which results from an increase in the size of existing cells, an increase in the number of cells, or both. Example- Growth of bone : Deposition of minerals between bone cells, causing the bone to grow in length and width. 5. Differentiation: It is the process where a cell changes from one cell type to another. Differentiation occurs numerous times during the development of a multicellular organism as it changes from a simple zygote to a complex system of tissues and cell types. It is the development of a cell from an unspecialized to a specialized state. Precursor cells, which can divide and give rise to cells that undergo differentiation, are known as **stem cells.
- Reproduction:** Reproduction (breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parents. In humans, the process occurs continuously throughout life, which continues from one generation to the next through the fertilization of an ovum by a sperm cell. INTRODUCTION TO VARIOUS BODY SYSTEMS S.No Organ Systems Components Functions
1. Skeleton System Bones, Cartilage Provides body structure and support.Bone marrow creates new blood cells for circulation;also stores lipids 2. Muscular System Skeletal muscle Allows body movement with bones. 3. Nervous System Brain,Spinal Cord,Cranial & Spinal Nerves Control and Coordination of all the body functions. 4. Cardiovascular System Heart,Arteries, Veins,Capillaries ,Blood Transports substances throughout the body. Circulates oxygen, CO2 heat, water, nutrients, wastes 5. Respiratory System Lungs, Diaphragm, Trachea,Bronchi,Alveoli Ventilation system for body Inhale oxygen and releases carbon dioxide out of the body. (Means gaseous exchange) 6. Lymphatic System ,Lymph,Lymphatic vessels,Lymph nodes, Spleen Works to help maintain ciculatory system as well as housing cells responsible for immunity. 7. Endocrine System Pituitary, Thyroid, Adrenals, Pancreas,hypothalmus Circulates hormones around the body to
- Maintaining the level of fluid in the body like- amount of blood,lymph and cerebrospinal fluid.
- Hormonal balance, etc. Components of Homeostasis: Homeostasis in the human body is continually intereferred and changed. Any disruptions come from the outside environment in any form of physical interruption such as extreme heat or cold . Other disruptions originate in the internal environment, such as a blood glucose level that falls too low when you skip breakfast. So, in order to maintain the internal balance of the body due to change made by the physical insults ,the homeostasis needed. The process of homeostasis is based on the feedback systems: Feedback Systems: A feedback system or feedback loop is a cycle of events in which the status of a body condition is monitored and evaluated then changed as per the requirements of body. Note: Important terms: 1.Controlled condition: Each monitored variable, such as body temperature, blood pressure, or blood glucose level, is termed a controlled condition. 2.Stimulus: Any disruption that changes a controlled condition is called a stimulus. A feedback system includes three basic components—a receptor, a control center, and an effector. Feed back systems have various components like: 1.Receptor 2.Control System 3.Effector
Feedback Systems:
1. Receptor: It is a structure that detects changes in a controlled condition and sends input to a control center. Input is in the form of nerve impulses or chemical signals. - For example, Thermoreceptors nerve endings in the skin sense temperature change (increase or decrease). 2. Control center : Mainly the brain, which sets the limit for controlled condition. It receives the input (in the form of hormones or nerve impulses or neurotransmitters) from receptors and generates output commands (in the form of hormones or nerve impulses or neurotransmitters) to the effector (organ of the body) when needed. 3. Effector : Mainly the organs of the body which receives output command generates from control center (brain) and produces a response or effect that changes the controlled condition. - For example: When your body temperature drops sharply(feeling cold), your brain (control center) sends nerve impulses (output) to your skeletal muscles (effectors). Then your body skeletal muscles starts shivering, which generates heat and raises your body temperature. The components of feed back systems works together in a cyclic manner to maintain the normal physiological balance.It can be maintained by two ways. 1. Negative Feedback 2. Positive Feedback 1.Negative feedback systems Negative feedback system works on the phenomenon of decrease the effects which is out of the limit means reverses a change in a controlled condition.
2.Positive feedback systems
- Opposite to negative feed back system where the responses negates,in positive feedback systems the change increase the response or you can say strenthen or reinforces the change.
- A positive feedback system works similarly to a negative feedback system, except for the way the response affects the controlled condition. Here also the receptor sense the change, gives signal to the control centre and the control centre gives command(output) to the target effector(organ where change/action needed).
- The control centre gives command to reinforce the action or you can say ,to increase the action rather decrease as in negative feedback systems.Due to this reinforcement and increase in the response,it is called as Positive feedback systems. Note: The action of a positive feedback system continues until it is interrupted by some mechanism.
- Example of Positive feedback system is the Child birth and role of Oxytocin Hormone.
- The contractions of labor (stimulus) push part of the fetus into the cervix, the lowest part of the uterus, which opens into the vagina.
- Stretch-sensitive nerve cells (stretch receptors) monitors the amount of stretching of the cervix. As stretching increases, they send more nerve impulses (input) to the brain (control center) , which in turn releases the hormone oxytocin (output) into the blood.
- Oxytocin causes muscles in the wall of the uterus (effector) to contract even more forcefully. The contractions push the fetus farther down the uterus, which stretches the cervix even more.
- The cycle of stretching and hormone release, and stronger contractions is interrupted only after the birth of the baby.
- As soon as birth takes place,the stretching of the cervix ceases and oxytocin is no longer released.
Note: As the fetus head stretches the cervix and releases of oxytocin increases more and more in cyclic manner until the birth takes place,such increase in the action or response by stimulus is called positive feed back systems where the change reinforces the previous action to occur in more forceful manner(positive response) till the stimulus ceases. BASIC ANATOMICAL TERMINOLOGY Body Positions Detail of any area or part of the human body in a specific stance called the anatomical position. Anatomical position is that when, the subject stands erect facing front with the head level and
Directional Terms: To locate various body structures, anatomists use specific directional terms, words that describe the position of one body part relative to another. Several directional terms are grouped in pairs that have opposite meanings, such as anterior (front) and posterior (back). Directional Terms Definition Example Superior Towards the head,or upper part of a structure Nose is superior to mouth. Inferior Away from head,lower part of the structure Stomach is inferior to lungs. Anterior Nearer to or at the front of the body Sternum is anterior to heart. Posterior Nearer to or back of the body Oesophagus is posterior to trachea. Medial Nearer to the midline Ulna is medial to radius. Lateral Farther from the midline Lungs are lateral to lungs. Ipsilateral On the same side of the body from another structure Gall bladder and ascending colon are ipsilateral. Contralateral On the opposite side of the body from another structure Ascending and descending colon are contralateral. Proximal Nearer to the attachment of a limb to the trunk Humerus is proximal to radius. Distal Farther from the attachment of a limb to the trunk Phalanges are distal to carpals. Superficial Toward or on the surface of the body Ribs are superficial to lungs.
Deep Away from the surface of the body Lungs are deep within ribcage. Diagram . Body Planes : Imaginary lines which divides body in different sections and parts.
- Sagittal plane :It is a vertical plane that divides the body or an organ into right and left sides. 2.Midsagittal plane or a median plane- A plane passes through the midline of the body or an organ then it divides the body or organs parts into equal right and left sides, it is called a Midsagittal plane or a median plane. 3.Parasagittal plane divides body parts into unequal right and left sides.
- Frontal or coronal plane divides the body or an organ into anterior (front) and posterior (back) portions.
Vertebral cavity Formed by 33 vertebral bone and surrounds spinal cord. Thoracic cavity Contains lungs and heart. Pleural cavity Surrounds lungs and made up of serous membrane containing pleural fluid. Pericardial cavity Surrounds heart and made up of serous membrane containing pericardial fluid. Mediastinum Central portion of thoracic cavity between lungs,contains heart,thymus and esophagus etc. Abdominal cavity Contains stomach, spleen, liver, gallbladder, small intestine,the serous membrane surrounds abdominal cavity called "peritonium". Pelvic cavity Contains urinary bladder,portions of large intestines and reproductive organs. Diagram showing various body cavities.
Abdominopelvic Regions and Quadrants To study the location of the many abdominal and pelvic organs , anatomists divide the body into horizontal and vertical line or in quadrants. The top horizontal line, the subcostal line, is drawn just inferior to the rib cage, , the bottom horizontal line, the transtubercular line, is drawn just inferior to the tops of the hip bones. Two vertical lines, the left and right midclavicular lines, are drawn through the midpoints of the clavicles (collar bones), just medial to the nipples. The four lines divide the abdominopelvic cavity into a larger middle section and smaller left and right sections. The names of the nine abdominopelvic regions are right hypochondriac, epigastric, left hypochondriac, right lumbar, umbilical, left lumbar, right inguinal (iliac), hypogastric (pubic), and left inguinal (iliac). The second method is simpler and divides the abdominopelvic cavity into quadrants. The names of the abdominopelvic quadrants are right upper quadrant (RUQ), left
CHAPTER- 2 CELL Learning Objectives: In this chapter students will explore the basic concepts of cell and its organelles, process of cell division,cell signalling(cell communication) and various types of transport mechanisms across plasma membrane.
Structure and Functions of Cell
ells are the smallest living subunits of a multicellular organism such as a human being. Microorganisms, such as amoebas and bacteria, are single cells that function independently. Human cells, however, must work together and function interdependently. Human cells vary in size, shape, and function. Most human cells are so small they can only be seen with the aid of a microscope and are measured in units called micrometers (formerly called microns). One micrometer= 1/1,000,000 of a meter or 1/25,000 of an inch. The branch of science which deals with the study of cell is termed as" Cytology ". Cell is first discoverd by Robert Hooke in 1665.Smallest cell is sperm cell. CELL: C
Definition : Cell is the basic structural and functional unit of life. The cell in the body may be multinucleated (more than one nucleus), anucleated (without nucleus) or uninucleated(one nucleus). For the purpose of study, cell may be divided into three main parts:
**1. Plasma membrane
- Cytoplasm**
