Advanced Biology Q4

• Tissue


  A group of cells that work together to carry out one or several functions in organisms such as plants and animals
• Four basic types of animal tissue

  • Epithelial tissue
  • Muscle tissue
  • Nervous tissue
  • Connective tissue

  
• Epithelial tissue


  • Made up of layers of tightly packed cells that line the surfaces of the body for protection, secretion, and absorption
  • Can be single-layered or multi-layered
  • Have the power to regenerate
  • Held together by gap junctions, tight junctions, zonula adheren, desmosomes, or interdigitation
  • Plasma membrane is specialized into flagella, cilia, and microvilli
• Classification of epithelial tissues

  • Sensory epithelium
  • Glandular epithelium
  • Pigmented epithelium
  • Absorptive epithelium
• Muscle tissue


  • Made up of cells containing contractile filaments that move past each other and change the size of the cell
  • Three types: smooth, skeletal, and cardiac
  • Helps in movement and locomotion
  • Supports the bones and other structures
  • Responsible for peristalsis and parturition
• Nervous tissue


  • Made up of the nerve cells (neurons) that together form the nervous system, including the brain and spinal cord
  • Neurons are the structural and functional units
  • Neuroglia provide support to the neurons and fibers
  • Neurosecretory cells function as endocrine organs and release chemicals from the axons directly into blood
• Connective tissue


  • Made up of many different types of cells that are all involved in structure and support of the body
  • Can be densely packed together, as bone cells are, or loosely packed, as adipose tissue (fat cells) are
  • Components: Intercellular Matrix, Cells, Fibers

  
• Bone, blood, fat, and cartilage are all connective tissues

  
• Connective tissues are made up of three types of fibers: collagen fibre, elastic fibre, and reticular fibre
• Digestion


  The process by which food and liquid are broken down into smaller parts so the body can use them to build and nourish cells and make energy
• Digestion


  1. Ingestion

  2. Absorption

  3. Elimination
• Mechanical digestion


  Breaking large pieces of food into smaller particles that can be acted upon by various enzymes, begins in the mouth with chewing/mastication and continues with churning and mixing actions in the stomach
• Chemical digestion


  Breaking down the complex molecules of carbohydrates, proteins, and fats into simpler forms using enzymes
• Digestion is an important process that breaks down proteins, fats, carbohydrates, vitamins, minerals into simpler forms so they can be absorbed easily into the body cells
• Digestion begins in the mouth, where food and liquids are taken in, and is completed in the small intestine

  
• The digestive system gets nutrients from food and hands it over to the blood and circulatory system then carries those nutrients, oxygen, and hormones to every cell and as these necessities are provided, waste products such as carbon dioxide are removed
• Circulatory system


  A network consisting of blood, blood vessels, and the heart that supplies tissues in the body with oxygen and other nutrients, transports hormones, and removes unnecessary waste products
• Heart


  • A muscular organ about the size of a fist, located just behind and slightly left of the breastbone
  • Made up of specialized cardiac muscle tissue that allows it to act as a pump within the circulatory system
  • Surrounded by a sac called the pericardium
  • Divided into four chambers - one atrium and one ventricle on each side
  • Atria receive blood and ventricles pump blood
• The heart is divided into four chambers
• The atria receive blood and the ventricles pump blood
• Muscular walls, called septa or septum, divide the heart into two sides
• Surrounding the heart is a sac called the pericardium

  
• The heart is a muscular organ about the size of a fist, located just behind and slightly left of the breastbone
• The heart is made up of specialized cardiac muscle tissue that allows it to act as a pump within the circulatory system
• Each individual body system works in conjunction with other body systems
• The brain is one of the important parts of the nervous system
• Nervous system


  Composed of the brain, the spinal cord, and the neurons. It is the body's storage center and control system, responsible for controlling and coordinating all the organ systems by sending messages from the brain through nerve signals
• Parts of the nervous system

  • Brain
  • Spinal cord
  • Neurons
• Neurons


  The fundamental units of the brain and nervous system, responsible for receiving sensory input, sending motor commands, and transforming and relaying electrical signals
• Neuron


  • Axons help in transmission of electrical impulses away from the cell body
  • Cell body consists of nucleus and other cellular components
  • Dendrites help in transmission of nerve impulse from one neuron to another and conduct nerve impulses towards the cell body
• Transmission of nerve impulse


  Dendrite of a neuron receives the nerve impulse from the axon terminal of the previous neuron
• Types of neurons

  • Sensory neurons
  • Motor neurons
  • Interneurons
• Sensory neurons


  Responsible for converting external stimuli from the environment into corresponding internal stimuli
• Motor neurons


  Located in the central nervous system, project their axons outside of the CNS to control muscles directly or indirectly
• Interneurons


  Act as the "middlemen" that form connections between sensory and motor neurons
• Central Nervous System (CNS)


  Composed of the brain and spinal cord, receives sensory information from the body and coordinates the body's responses
• The nervous system is divided into two major parts: the Central Nervous System and the Peripheral Nervous System
• The nervous system makes sure that all the parts of the body are working together efficiently
• Nerve impulse


  Transmitted from one neuron to another neuron when the dendrite of a neuron receives the nerve impulse from the axon terminal of the previous neuron
• Types of Neurons

  • Sensory neurons
  • Motor neurons
  • Interneurons