Animal tissue

• Tissues are groups of similar cells that perform a particular function
• Types of animal tissue

  • Epithelial tissue
  • Connective tissue
  • Muscle tissue
  • Nerve tissue

  
• Epithelial tissue


  • Forms the outer layer of the body and also lines many of the bodies cavities where it has a protective function
• Connective tissue


  • Assists in support and protection of organs and limbs and depending on the location in the body it may join or separate organs or parts of the body
• Muscle tissue


  • Enables various forms of movement, both voluntary and involuntary
• Nerve tissue


  • Responsible for the carrying of electrical and chemical signals and impulses from the brain and central nervous system to the periphery, and vice versa
• Types of epithelial tissue

  • Squamous epithelium
  • Cuboidal epithelium
  • Columnar epithelium
  • Ciliated columnar epithelium

  
• Squamous epithelium


  Thin and flat oval-shaped cells that are elliptical in shape and lie on the basement membrane. Simple squamous epithelium is one cell thick. Stratified squamous epithelium consists of many layers
• Squamous epithelium


  • Responsible for diffusion. Thin structure allows for movement of substances across the cells. Protects underlying parts and prevents friction
• Cuboidal epithelium


  Cube-like in structure; may occasionally have structures called microvilli on surface to aid absorption. Nuclei is in the middle of the cell

  
• Cuboidal epithelium


  • Secretion and absorption is the main functions. Also serves as a protective function against bacteria and the wearing away of certain organs by lining various structures. Also prevent water loss
• Columnar epithelium


  Elongated cells, nuclei located at the base of the cell. Cells connected by tight junctions and receive their nutrients from the basement membrane. Goblet cells secrete mucus that is interspersed
• Columnar epithelium


  • Absorption, secretion and sensory function. The main function is protective. Prevent against bacterial infection. Can also secrete mucus to protect surface from damage
• Ciliated columnar epithelium


  Consists of columnar cells with exceptionally fine hairs, known as cilia, on the free ends of the cell. Goblet cells secrete mucus
• Ciliated columnar epithelium


  • Traps dust particles and moves it away from the lungs. Detects stimuli is sensory organs
• Striated muscle tissue


  Made up of a large number of muscle fibres which is a long, cylindrical cell. It contains light and dark bands, hence the name 'striated'. The content of the muscle fibre consists of cytoplasm (sarcoplasm), a large number of oval nuclei, and mitochondria enclosed by a thin elastic cell membrane, the sarcolemma
• Striated muscle tissue


  • Work in pairs, contracting and relaxing voluntary and involuntary which results in movement of body parts
• Smooth muscle tissue


  Consists of spindle-shaped muscle fibres, with one large oval cell nucleus per fibre. The contents of smooth muscle fibres also include sarcoplasm (cytoplasm) which is enclosed by a cell membrane (sarcolemma)
• Smooth muscle tissue


  • The involuntary contraction and relaxation of smooth muscle fibres results in slow, rhythmic movements. This ensures for example peristalsis in the digestive system and regulates blood flow in the arteries
• Cardiac muscle tissue


  Consist of branched muscle fibres that are connected to one another by means of muscular (myocardial) bridges. The muscular bridges ensure that the cardiac muscle functions as a unit. Intercalated discs (dark bands) are part of the sarcolemma and speed up the transmission of impulses. The contents also include sarcoplasm, which is enclosed by a thinner sarcolemma
• Cardiac muscle tissue


  • Displays automatism, which causes the uninterrupted, involuntary contraction and relaxation of the heart
• Nerve tissue


  Cells that make up the central nervous system and peripheral nervous system are classified as nerve tissue. In the central nervous system, nerve tissue forms the brain and spinal cord. In the peripheral nervous system, the nerve tissue forms the cranial nerves and spinal nerves, which include the sensory and motor neurons
• Nerve tissue


  • The function of nerve tissue is to transmit nerve impulses around the body. Nerves consist of a cell body (soma), dendrites, which receive impulses, and axons that send impulses. The axons of neurons are surrounded by a myelin sheath. The myelin sheath consists of layers of myelin, a white fatty substance. The main function of the myelin sheath is to insulate the nerve fibres and it also increases the speed of the impulses transmitted through the nerve cell
• Nerve tissue


  Involuntary contraction and relaxation of the heart
• Nerve tissue


  • Cells that make up the central nervous system and peripheral nervous system
• Nerve tissue


  1. Nerve tissue in the central nervous system forms the brain and spinal cord

  2. Nerve tissue in the peripheral nervous system forms the cranial nerves and spinal nerves, which include the sensory and motor neurons
• Function of nerve tissue


  To transmit nerve impulses around the body
• Types of nerve cells

  • Sensory neurons
  • Interneurons
  • Motor neurons
• Sensory neurons


  Conduct nerve impulses from receptors to the central nervous system
• Motor neurons


  Conduct nerve impulses from the central nervous system to the effectors (muscles and glands)
• Interneurons


  Conduct nerve impulses between the sensory and motor neurons in the brain and spinal cord
• Connective tissue


  Biological tissue that is important for supporting, connecting or separating different types of tissues and organs in the body
• Connective tissue


  • Consists of cells, fibers (like collagen) and extracellular matrix
  • The type of intercellular matrix differs in different connective tissues
  • There are different types of connective tissue with different functions
• Areolar connective tissue


  • Forms a continuous layer under the skin and loosely connects the skin to muscles
  • Fills spaces between organs, blood vessels, nerves and muscles
• Areolar connective tissue


  • Jelly matrix; has a network of elastic fibers that are interconnected
  • Yellow elastic fibers (branched)
  • White inelastic collagen fibers (parallel)
• Function of areolar connective tissue

  • Holds the organs in place, cushions and protects organs (serves as packing material)
  • Acts as insulating material
• Dense connective tissue


  Joins muscle to bone (tendons) and bone to bone (ligaments)
• Dense connective tissue


  • Small amount of matrix and a small number of cells
  • Large number of fibers that run parallel
  • White = inelastic collagen fibers (tendon)
  • Yellow = elastic fibers (ligaments)
• Function of dense connective tissue

  • Muscle contraction and relaxation to make the bone move
  • Degree of movement in the joints
• Cartilage


  • Tough rubber matrix consisting of protein (chondrin), can be flexible or stiff
  • Matrix has fluid-filled spaces (lacunae)
  • Lacunae are cartilage cells that occur singly or in groups