Organizing principles of human body

Hierarchy of Structural Organization Each of these build upon one another to make up the next level: Chemical level Cellular Tissue Organ Organ system Organism

Hierarchy of Structural Organization Chemical level Atoms combine to make molecules 4 macromolecules in the body  Carbohydrates  Lipids  Proteins  Nucleic acids

Hierarchy of Structural Organization Cellular Made up of cells and cellular organelles (molecules)  Cells can be eukaryotic or prokaryotic  Organelles are structures within cells that perform dedicated functions (“small organs”)

Hierarchy of Structural Organization Tissue Collection of cells that work together to perform a specialized function 4 basic types of tissue in the human body:  Epithelium  Connective tissue  Muscle tissue  Nervous tissue

Hierarchy of Structural Organization Organ Made up of tissue  Heart  Brain  Liver  Pancreas, etc…… Pg 181

Hierarchy of Structural Organization Organ system (11) Made up of a group of related organs that work together  Integumentary  Skeletal  Muscular  Nervous  Endocrine  Cardiovascular  Lymphatic  Respiratory  Digestive  Urinary  Reproductive Circulatory Pg 341 Urinary System

Levels of Organization: COHN – 99.5% 99.9% = See figs. 1.3 & 1.4

Hierarchy of Structural Organization Organism An individual human, animal, plant, etc…… Made up all of the organ systems Work together to sustain life

The Cell Cells: structural and functional units of all living organisms. building blocks of the human body. adult human body contains ~ 75 trillion cells. Each cell type performs specific functions. ~200 cell types in humans  subcategories of most

Common Characteristics of Cells Perform the general functions necessary to sustain life: Obtain nutrients and other materials from its surrounding fluids.  Fuel molecules, O 2, building blocks, minerals,etc Dispose of wastes products  Urea (from nitrogen), CO 2, metabolic waste Maintain shape and integrity  Size and shape are related to function Cell division:  Mitosis: growth and repair  Meiosis: gamete formation

Study of Cells Cytology: study of cells Microscopic anatomy Individual cells observable by light microscopy Subcellular structures observable by electron microscopy.  TEM  SEM Unit of measure: micrometer (um) RBC: 7-8um

2. Bilateral Symmetry - left half of the body is a mirror image of the right half. - structures in the median plane are unpaired, but have identical left and right sides.

Cells Parts of a cell Cell Membrane (or plasma membrane) Cytoplasm  Cytosol  Organelles Membranous Organelles Non-membranous Organelles  Inclusions Nucleus

Plasma (Cell) Membrane the outer, limiting barrier separates the internal contents of the cell from external materials.

Cytoplasm general term for all cellular contents located between the plasma membrane and the nucleus.

Nucleus “control center” of the cell controls protein synthesis directs the functional and structural characteristics of the cell.

Plasma membrane: composition Lipids Phospholipids  Head: hydrophilic  Tail: hydrophobic  Form lipid bilayer Cholesterol Glycolipids  Carbohydrate component  Part of glycocalyx

Plasma membrane: composition Protein Integral membrane proteins Peripheral membrane proteins Some serve as enzymes, ion channels or receptors Glycoproteins

Fertilization: Four Major Steps 1. Sperm contacts the egg 2. Sperm or its nucleus enters the egg 3. Egg becomes activated and developmental changes begin 4. Sperm and egg nuclei fuse

Words to know… Fuse- to physically join together Ovum – egg cell (female gamete) Cleavage – process of cell division during development Differentiation – the process of forming different kinds of cells from similar cells of the early embryo Embryo – an organism in an early stage of development Morula – solid ball of cells formed from cleavage Blastula – hollow ball of cells formed from cleavage Gastrula – a hollow ball of cells with an “in pushing” and 3 layers (germ layers)

Fertilization

The Nuclei Fuse Together

Development of the zygote, the study of which is known as embryology or developmental biology. The zygote undergoes a series of mitotic cell divisions called cleavage. The stages of development are: Fertilized ovum (zygote)  2-cell stage  4-cell stage  8-cell stage  Morula  Blastula  Early Gastrula  Late Gastrula

Cleavage (divide via mitosis) forms the 2 cell stage

And eventually form a Morula

And next, a gastrula

The Regents Diagram… Sperm and ovum 1. Zygote (fertilized ovum) 2. 2-cell stage 3. 4-cell stage 4. Morula 5. Blastula 6. Gastrula

Differentiation (Organogenesis) Organogenesis is the formation of the organs (Organo = organs, genesis = creation) Arises from the layering of cells that occurs during gastrula stage The layers are germ layers; they have specific fates in the developing embryo: Endoderm  The innermost layer  Goes on to form the gut Mesoderm  In the middle  Goes on to form the muscles, circulatory system, blood and many different organs Ectoderm  The outermost  Goes on to form the skin and nervous system

Late Gastrula Mesoderm Endoderm Ectoderm

Differentiation of Primary Germ Layers (from the gastrula) EctodermMesoder m Endoderm Nervous system SkeletonDigestive tract Epidermis of skin MusclesRespiratory system Circulatory system Liver, pancreas GonadsBladder

Early Human Development Summary Meiosis makes sperm in males and ovum in females Sperm and ovum unite nuclei to form a zygote Zygote undergoes cleavage and becomes gastrula with 3 germ layers

11 Organ systems different organs work together to provide specialized functions  Body Coverings  Support & Movement  Integration & coordination  Transport  Absorption / Excretion  Reproduction