Organización General de los Organismos

Study Notes

Living organisms can be unicellular or multicellular, with multicellular organisms being more complex structurally.
Fundamental structural levels include:
- Chemical level: basic structures forming cells (atoms and molecules), no vital functions.
- Cellular level: basic unit of life, carries out vital functions like reproduction, relationship, and nutrition.
- Tissue level: association of cells, carries out specialized functions.
- Organ level: various tissue associations, performing complex functions.
- Systems and apparatuses (organism):
  - Systems: collections of similar organs working independently, for a specific function (9 systems).
  - Apparatuses: collections of different organs working together (6 apparatuses).

Cells are the structural and functional units of living things.
They carry out vital functions (nutrition, relationship, reproduction).
Cells can be:
- Prokaryotic: lack a defined nucleus, genetic material (DNA) is free in the cytoplasm.
- Examples of prokaryotic cells are bacteria.
  - Size range is between 1 and 10 micrometers.
- Eukaryotic: possess a well-defined nucleus, genetic material (DNA) enclosed by a nuclear membrane.
All cells share common structures: plasma membrane, cytoplasm, and genetic material (DNA).

Nutrition is how organisms procure and use nutrients for survival.
Cells intake nutrients in various ways:
- Passive transport: movement of substances across the membrane without energy input (diffusion, facilitated diffusion, osmosis, ultrafiltration).
- Active transport: movement of substances against a concentration gradient, requiring energy (ATP).

Reproduction is the process by which organisms create new individuals.
Mitosis: cell division, producing two identical daughter cells.
- Phases: prophase, metaphase, anaphase, telophase, cytokinesis.
Meiosis: cell division involved in sexual reproduction, producing daughter cells with half the number of chromosomes.

Relationship, also known as "reception and response" in cells refers to how cells react to stimuli.
Cells receive stimuli from the environment either internally or externally.
Cells respond to stimuli using several mechanisms that help them survive, and function properly in their environment.
Communication, between cells, allows them to work together in a coordinated manner.

Epithelial tissue: Covers body surfaces, lines body cavities, forms glands.
- Classification by layering (simple, stratified, pseudostratified) and shape (squamous, cuboidal, columnar).
- Function: protection, secretion, absorption, excretion.
Connective tissue: Supports, connects, and separates different tissues and organs in the body.
- Classification: Loose connective tissue, dense connective tissue, cartilage, bone, blood.
- Function: support, protection, insulation, transportation.
Muscle tissue: Contractile tissue, responsible for movement.
- Classification: Skeletal muscle, cardiac muscle, smooth muscle.
- Function: movement, support, heat production
Nervous tissue: Processes information and coordinates body functions.
- Classification: Neurons, neuroglia.
- Function: communication, control, coordination

Human Organs: Specific configurations of tissues that provide a particular function.
- Examples: heart, lungs, brain, kidney, skin, liver
Systems: Groups of organs that work together to perform a major function.
- Examples: digestive system, circulatory system, nervous system, etc.
Organs systems are comprised of groups of organs working collaboratively to fulfill a specific function.

Body Planes: Imaginary lines used to section the body for description purposes.
- (Frontal, sagittal, transverse)
Body Regions: Divisions of the body for clinical and anatomical descriptions.
Body Cavities: Internal spaces that enclose vital organs.
- (Dorsal cavity, ventral cavity (thoracic and abdominal cavities)

Blood: Specialized connective tissue. Fluid matrix (plasma), cells (red blood cells, white blood cells, platelets).
- Function: transportation, immunity, blood clotting.

Blood types are determined by the presence or absence of specific antigens on red blood cell surfaces.
- ABO system (A, B, AB, O) and Rh factor (positive or negative)
Blood typing is crucial for transfusions and diagnosing diseases like blood disorders.