MMED1005 Lecture Notes - Lecture 2: Trachea, Muscle Tissue, Nervous Tissue
Development and Physiology
Embryogenesis: process – embryo is formed, developed.
- Fertilisation of the ovum (egg)
- After fertilization is called a zygote
- Zygote undergoes rapid cell divisions (mitosis) and cellular differentiation
- Leads to development of an embryo
Ontogenesis: process – growth of individual organisms
- Cell division (with eventual growth)
- Cell differentiation
- Cell migration – give rise to the organs
- Organogenesis (origin of organs)
Differentiation into three layers (about 250 kinds of cells in humans)
- Ectoderm (external layer)
o Skin cells of epidermis
o Neuron of brain
o Pigment cell
- Mesoderm (middle layer)
o Cardiac muscle
o Skeletal muscle cells
o Tubule cell of the kidney
o Red blood cells
o Smooth muscle (in gut)
- Endoderm (internal layer)
o Lung cell (alveolar cell)
o Thyroid cell
o Pancreatic cell
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Document Summary
Zygote undergoes rapid cell divisions (mitosis) and cellular differentiation. Cell migration give rise to the organs. Differentiation into three layers (about 250 kinds of cells in humans) Ectoderm (external layer: skin cells of epidermis, neuron of brain, pigment cell. Mesoderm (middle layer: cardiac muscle, skeletal muscle cells, tubule cell of the kidney, red blood cells, smooth muscle (in gut) Endoderm (internal layer: lung cell (alveolar cell, thyroid cell, pancreatic cell. At 10 weeks, called a human feotus. The grown living body is made of cells: Like all living organisms obeys the second law of thermodynamics, transfers chemical (glucose) energy into work and (irreversibly) heat. Takes in fuel, and oxygen to burn the fuel. Is an open dissipative system in a state of dynamic stability maintained by a flow of energy until collapses down to its elements, molecules and atoms (death) Levels of organisation of the body, macroscopic to microscopic sizes. Tissues groups of cells of similar specialization.