Biology

• NERVOUS SYSTEM

  • receives and detects signals from the surroundings and after detecting that signal, it sends it to the brain.
• Central Nervous System

  • It consists of the brain and spinal cord. It’s location is in the head and continues along the back.
  • In all the vertebrates, the central nervous system comprises the brain and the spinal cord.
• BRAIN

  • Its main function is to control thoughts and body movement.
  • helps getting messages and responses to the body.
• FOREBRAIN

  • t is anterior most part of the brain consists of Cerebrum, Hypothalamus and Thalamus.
• MIDBRAIN

  • region of the developing vertebrate brain. serves important functions in motor movement, particularly movements of the eye, and in auditory and visual processing.
• HINDBRAIN

  • It is the central region of the brain which is made up of Cerebellum, Medulla and Pons.
• SPINAL CORD

  • a cylindrical bunch of nerves, which is enclosed by spine. This spine connects all parts of the human body to the brain.
• Peripheral Nervous System

  • consists of all the nerves continuing from the central nervous system to the entire body. It is the lateral most part of the human nervous system which helps in connecting different parts of the body with CNS.
• Afferent nerve fibers

  • These nerve fibers are responsible for transmission of messages from tissues and organs to the central nervous system.
• Efferent nerve-fibers

  • These nerve fibers are responsible for sending messages from CNS to the corresponding peripheral organ.
• Somatic Neural System (SNS)

  • This neural system controls all the voluntary actions in the body by transmitting impulses from CNS to skeletal muscle cells.
• Autonomic neural system (ANS)

  • controls all the involuntary actions of the body like regulation of physiological functions (digestion, respiration, salivation, etc.).
• Autonomic Nervous System

  • It is made up of both sympathetic and parasympathetic nerves.
• Parasympathetic nerves

  • restores the body to a calm and composed state and prevents it from overworking
• Sympathetic nerve

  • prepares the body for fight and flight response.
• Cerebral Cortex (Parts of Brain)

  • It controls the Voluntary movement, reasoning, perception.
• Cerebellum (Parts of Brain)

  • It helps in maintaining balance, movement and body posture. It further gets splitted into two hemispheres.
• Hypothalamus (Parts of Brain)

  • This part of the brain is responsible for the regulation of the temperature of the body, hunger centre, emotions, regulation of the circadian rhythms etc.
• Medulla oblongata (Parts of Brain)

  • It is also known as brain stem. It regulates functions like heart rate, breathing and blood pressure
• Thalamus (Parts of Brain)

  • It regulates the motor and sensory information and obtains the sensory information which further carries forward the information to the cerebral cortex.
• Limbic system (Parts of Brain)

  • It helps in maintaining the response to different emotions.
• Basal Ganglia (Parts of Brain)

  • It maintains the movements and balance and also has the caudate nucleus, globus pallidus, putamen, substantia nigra and subthalamic nucleus.
• Midbrain (Parts of Brain)

  • It controls various functions like hearing, vision, body movement, eye movement.
• Neurons

  • are known as structural and functional units of the nervous system. It is of irregular shape and has the capability to conduct electrical signals.
• Dendrite

  • It is the shortest fiber in the cell and extends out from the cell body of a neuron.
• Axon

  • It is considered as the longest thread in the human body of a neuron and also covered by insulating and protective covering of sheath known as myelin sheath.
• Cell body

  • It is made up of cytoplasm and nucleus.
• Synapse

  • Gap present between adjacent pairs of neurons, through which nerve impulses pass is known as _______
• hómoios = same
• stásis = steady
• HOMEOSTASIS

  • refers to any process that living things use to actively maintain fairly stable conditions necessary for survival. 
• Walter Cannon

  • Physician that coined the term “Homeostasis” in 1930
  • His book, The Wisdom of the Body, describes how the human body maintains steady levels of temperature and other vital conditions such as the water, salt, sugar, protein, fat, calcium, and oxygen contents of the blood.
  • In short, it is how humans can maintain balance even when the environment changes.
• IMPORTANCE OF HOMEOSTASIS

  • The failure of homeostatic regulation in just one body system will cause conditions to deteriorate and it may be fatal.
  • For the health of an organism, all homeostatic regulation mechanisms must function properly.
• CONDITIONS MAINTAINED BY HOMEOSTASIS

  • PROPER CONCENTRATION OF GASES, NUTRIENTS, WATER, AND SALTS
  • OPTIMUM TEMPERATURE
  • OPTIMUM PRESSURE
• oxygen

  • necessary for the process of metabolic reactions and cellular respiration to produce energy for the body
• carbon dioxide

  • waste product of this process but also must be present in certain amounts for other processes to occur efficiently. The accumulation of CO₂ can be toxic.
• Nutrients

  • provide reactants, enzymes, cofactors, and energy for chemical reactions.
• Water and salts

  • determine the fluid balance, electrolyte balance, and the pH of the body.
• OPTIMUM TEMPERATURE

  Normal Temperature

  • 37C
• Influence on Chemical Reaction

  • The rates of chemical reactions are temperature dependent