Gen Biology 2

• If we were to "break apart" the human body at the microscopic level, then the cell would constitute its most basic unit
• The average adult has somewhere between 30 – 40 trillion cells, and an estimated 242 billion new cells are produced every day
• When a select group of cells with similar functions come together, it forms a tissue
• Tissues cumulate into organs, group of organs form organ systems and eventually, a complete organism
• Levels of organization in the human body

  • Cells
  • Tissues
  • Organs
  • Organ Systems
  • Organism
• Human Anatomy


  The scientific study of form and shapes of human beings
• Skeleton


  • Enables a variety of movements from walking and running to crawling, jumping and climbing
  • Protects several vital organs such as the heart, lungs and the liver
  • Bones are attached to other bones through ligaments, a fibrous connective tissue
• Joints


  • The points at which two or more bones meet
  • Enable a range of movements like rotation, abduction, adduction, protraction, retraction and more
  • Can be classified into movable joints and immovable joints
• Muscles


  • Specialised tissues which assist the bones in locomotion
  • Attached to the bones through tendons
  • Movement of limbs happens due to the contraction and relaxation of the corresponding muscles present in that region
  • Most movement involves muscles that work as a pair
• Humans have evolved separately from other animals, but since we share a distant common ancestor, we mostly have a body plan that is similar to other organisms, with just the muscles and bones in different proportions
• Despite being incredibly tall, giraffes have the same number of vertebrae as humans, i.e. seven vertebrae in their neck
• Ability to use our hands

  • Especially for tasks that require dexterity, such as writing, opening a bottle of water, opening a doorknob, etc.
  • Result of humans having ancestors that began walking on their hind limbs rather than using all four limbs
• Most of our anatomical insight was gained through the dissection of corpses (cadavers), and for a long time, it was the only way we could gain anatomical knowledge about the human body
• In 2018, scientists had discovered a new, body-wide organ called the Interstitium that exists right under the skin
• Human Physiology


  The physical, mechanical, and biochemical function of humans
• Claude Bernard is referred to as the father of Physiology for his exemplary research
• Crucial human body parts for survival

  • Brain
  • Heart
  • Liver
  • Lungs
  • Kidneys
• Circulatory System


  • Comprises the heart and all the blood vessels: arteries, capillaries, and veins
  • Has two components: Systemic circulation and Pulmonary circulation
  • Also has a third type called Coronary circulation
  • Blood is the body's "transport system" that helps to transport essential nutrients and minerals to the cells and waste byproducts away from it
• Digestive System


  • Breaks down food and assimilates nutrients into the body
  • Major components: Mouth, Teeth, Tongue, Oesophagus, Stomach, Liver, Pancreas, Gastrointestinal tract, Small and large intestines, Rectum
  • Process of digestion starts with mastication (chewing food) and involves secretion of acids, enzymes and bile to break down food
• Reproductive System


  • Varies for males and females
  • Female system includes ovaries, uterine tubes, uterus, cervix, and vagina
  • Male system includes testicles, vas deferens, seminal glands, prostate gland, and Cowper's gland
• Respiratory System


  • Involves the intake of oxygen and the exhale of carbon dioxide
  • Comprises trachea, bronchi, bronchioles, lungs, and diaphragm
  • Gas exchange occurs through alveoli (air sacs) in the lungs
• Nervous System


  • Maintains voluntary and involuntary actions
  • Classified into Central Nervous System (brain and spinal cord) and Peripheral Nervous System (nerves and ganglia)
  • Central Nervous System includes forebrain, midbrain, and hindbrain
  • Peripheral Nervous System includes somatic and autonomic nervous systems
• Forebrain


  Sexual development and emotion functions are attached to it
• Midbrain


  • Situated between the hypothalamus and thalamus
  • Associated with the brain stem
  • Auditory and visual responses are controlled by it
• Hindbrain


  • The medulla, pons, and cerebellum are together, tied in it
  • Interconnections of different parts of the brain's surface that helps to accommodate neurons and connect them to the spinal column are done by it
• Parts of the Peripheral Nervous System

  • Somatic nervous system
  • Autonomic Nervous System
• Somatic nervous system


  • Its primary purpose is to transmit the motor and sensory impulses from CNS and back
  • It is linked to all the sensory organs, limbs and skeletal system
• Autonomic Nervous System


  • Works without the person's effort
  • Relays impulse from the central nervous system to smooth muscles and involuntary organs such as heart, lungs etc.
  • Prepares the body against any violent attacks or abnormal conditions such as high body temperature during a fever or high rate of breathing and blood pressure after a strenuous exercise
• Every human being, tissues, human body parts and the organ systems are made up of cells- the fundamental unit of life
• Anatomy


  The science of understanding the structure and the parts of living organisms
• Physiology


  Deals with the internal mechanisms and the processes that work towards sustaining life
• With the progress of evolution, organisms began to exhibit advanced characteristics and features that enabled them to be more efficient and thrive in their respective environment
• Human structure

  • Bipedal, with hair covering the body, presence of mammary glands and a set of extremely well-developed sense organs
• Human body anatomy


  • Specialized circulatory system that enables the efficient transport of materials and nutrients within the body
  • Well-developed digestive system that helps to extract essential nutrients and minerals required by the body
  • Well developed respiratory system that ensures the efficient gas exchange
  • Nervous system that enables coordination and interaction within the body and also the external environment, thereby ensuring survival
• Claude Bernard is the father of human Physiology
• Andreas Vesalius is known as the father of human anatomy
• Types of anatomy

  • Gross anatomy
  • Microscopic anatomy
• Gross anatomy

  Deals with things that can be seen with the naked eyes
• Microscopic anatomy


  Deals with the things that can only be viewed under a microscope
• Anatomy


  Helps us to understand the structure and relationship of all parts of the body