Cell Types Quiz

Study Notes

Cells are classified based on whether they function independently or as part of a tissue.
Red blood cells are examples of cells that function individually and move freely through the circulatory system to transport oxygen.
Epithelial cells, like those lining the respiratory tract, are attached and work together as a tissue to protect the system.
Some cells, such as skin cells, can rapidly divide to replace damaged or lost cells.
Other cells, like nerve cells, only divide under specific conditions, hence injuries like spinal cord damage often can't heal.
Many cells are specialized to produce and secrete substances, like insulin (produced by pancreatic cells) to regulate blood sugar or mucus produced by epithelial cells in the lungs.
Despite working in diverse ways, all cells within an organism have the same genetic material.
Cellular differentiation arises from the regulation of genes. Different genes are expressed in different cell types to create the variety of cell functions.

There are four main subtypes of bone cells:
- Osteocytes: maintain bone tissue.
- Osteoblasts: form the bone matrix.
- Osteogenic cells: stem cells that differentiate into osteoblasts.
- Osteoclasts: resorb bone.

Leukocytes are crucial immune system cells that vary in function and proportion in the blood.
Monocytes engulf and destroy pathogens (5% of leukocytes).
Eosinophils target large parasites and mediate allergic responses (2% of leukocytes).
Basophils release histamines for inflammation (less than 1% of leukocytes).
Lymphocytes include B cells (produce antibodies against non-self-antigens) and T cells (destroy infected or cancerous cells) (about 30% of leukocytes).
Neutrophils are the most abundant type (about 62% of leukocytes), phagocytosing single-celled bacteria and fungi in the blood.

Tissues are groups of cells that work together to perform a specific function.
Plant and animal tissues can have cells of the same type or multiple types in the same tissue. There are four main types of human tissues:
- Connective
- Epithelial
- Muscle
- Nervous

Connective tissue is diverse and abundant in various forms.
The matrix of connective tissue determines its properties, from fluid (blood plasma) to gel-like to solid (bone).
Connective tissue types include:
- Connective tissue proper
  - Loose connective tissue
  - Dense connective tissue
- Cartilage: hyaline, elastic, fibrocartilage
- Bone -Blood

Muscle tissue is for movement.
Types include:
- Skeletal muscle(striated): movement from pulling on bones; voluntary
- Smooth muscle(non-striated): found in internal organs; involuntary
- Cardiac muscle(striated): found in the heart; involuntary

Nervous tissue is composed of neurons (transmit electrical signals) and glial cells (support neuronal function).
Nervous tissue forms the central nervous system (brain and spinal cord) and peripheral nervous system.
Types of nervous tissue include gray and white matter, nerves, and ganglia.