General Human Anatomy

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BODY CAVITIES

DORSAL BODY CAVITIES

Cranial cavity
- Space inside the skull
Spinal cavity
- From the cranial cavity to the end of the spinal cord
- Spinal cord
  - Continuation of the brain
  - Protected by the bony vertebrae which surround the spinal cavity and form the spine.

VENTRAL BODY CAVITIES

Contains the structures within the chest and abdomen (visceral organs).
Thoracic cavity
- Separated from the abdominal cavity by the dome-shaped muscle - the diaphragm
- Contains the heart and lungs
- Mediastinum divides the lungs into the right and left cavities.
  - The right lung has 3 lobes
  - The left lung has 2 lobes
Abdominopelvic cavity
- Abdominal: stomach, liver, intestines, etc.
- Pelvic: reproductive organs, bladder, etc.

OTHER BODY CAVITIES

Oral and Digestive Cavity
- Continuous to the digestive organs until the anus.
Nasal Cavity
- Posterior to the nose; part of the respiratory system.
Orbital Cavities
- Houses the eyes.
Middle Ear Cavity
- Contains tiny bones for hearing.

THE HUMAN CELL

PARTS OF A CELL

Nucleus

Control center of the cell
Contains the genetic material or DNA

3 regions of the nucleus

- Nuclear membrane

A double phospholipid membrane that allows the exchange of materials with the rest of the cells.

- - Has pores where materials pass through.
- Nucleoli
  - The nucleus contains one or more nucleoli which are sites for ribosome production
- Chromatin
  - Condenses to form chromosomes during cell division.

Plasma Membrane

Double phospholipid layer with hydrophilic ( water-loving ) and hydrophobic ( water-fearing ) tails.
Microvilli - finger-like projections that increase the area for absorption.

Membrane Junctions

Binds different types of cells

3 types of junctions:

- Tight junctions
  - Binds junctions into leak-proof sheets; acts like zippers.
  - Can be found in the small intestines
- Desmosomes
  - Prevent cells subjected to mechanical trees not to be pulled apart.
- Gap junctions
  - Communicating junctions
  - Can be found in the heart

Cytoplasm

Material outside the nucleus where the other organelles are located.

Ribosomes

Sites of protein synthesis
Made of RNA

Endoplasmic reticulum

Rough ER: studded with ribosomes; where materials of the membrane are formed.

Smooth ER: cholesterol synthesis, fat metabolism, detoxification of drugs.

Golgi Apparatus

Modifies and packages proteins
Has a cis and trans face
- Cis face - receiving side, nearer the nucleus and RER, receives the transport vesicles.
- Trans face - shipping side, exudes the secretory vesicles.

Lysosomes

Digest non-usable materials.
suicide “bags” of the cell.

Peroxisomes

Sacs of oxidase enzymes.
Break down free radicals.

Mitochondria

A powerhouse of the cell.
Provides ATP - adenosine triphosphate for cellular energy and processes.

Cytoskeleton

Provides a cell with an internal framework.
3 types:
- Microfilaments: Cell motility
- Intermediate filaments: Help desmosomes that the cell will not be pulled apart.
- Microtubules: Determine the overall shape of the cell.

Centrioles

Generation of microtubules; formation of the mitotic spindle during cell division.

Cilia

Whip-like extensions that move substances along the cell surface.

Flagella

Projections that are basically longer
The only flagellated cell in the human body is the sperm.

DIFFERENT CELLS OF THE BODY

Cells that connect body parts.
- Fibroblast: makes and secretes protein building blocks.
- Erythrocyte / RBC: carries oxygen in the blood
Cells that cover and line body organs
- Epithelial cells: resist tearing when the epithelium is rubbed or pulled because of the presence of desmosomes.
Cells that move organs and body parts.
- Skeletal, cardiac, smooth muscle cells: shorten forcefully and move the bones, and pump blood.
Cells that store nutrients.
- Fat: produced by a large lipid droplet in its cytoplasm.
A cell that fights diseases.
- WBC such as macrophage: crawls to tissues to reach infection sites.
Cells that gather information and control body function.
- Nerve cell/neuron: receives and transmits messages.
Cells of reproduction
- Oocyte: largest cell in the body.
- Sperm: has tail built for swimming to the egg for fertilization.

TISSUES

Group of cells with similar structure and function

Terms to remember:
- Hyperplasia: increase in the number of tissues or organs
- Atrophy: decrease in size of tissues or organs
- Hypertrophy: increase in the size of tissues or organs.
- Metaplasia: the transformation of one differentiated cell type to another differentiated cell type.

CONNECTIVE TISSUES

Function: binds tissues together, protection and support.
Some are vascular, some are avascular.

Bone

Composed of osteocytes or bone cells located in lacunae or cavities, calcium salts, and collagen fibers.

Cartilage

Composed of chondrocyte or cartilage cell
Less hard and is more flexible than bone.

Dense Connective Tissue

Main matrix element: collagen fiber
Found in:
- Tendons - attach muscle to bone.
- Ligaments - attach bone to bone at joints.
- Dermis - lower layers of the skin.

Reticular Connective Tissue

Forms stroma of lymphoid organs.

Blood ( Vascular Tissue )

Transport vehicle for a cardiovascular system for carrying nutrients and wastes.
Blood plasma - blood cells surrounded by fluid matrix.

Loose Connective Tissue

Areolar tissue - most widely distributed connective tissue.
Adipose tissue - for insulation, protection, and site for fuel storage.

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