Additional Stage 1 Biology B Exam Study Flashcards
Organism hierarchy:
Cell, tissue, organ, system.
E.g:
Muscle cells form muscle tissue.
Muscle tissue combines with the nerve & connective tissues to form the heart (organ).
The heart combines with other structures (lungs, blood vessels, blood) to make up the circulatory system.
What are stem cells?
Stem cells are undifferentiated cells produced in the bone marrow that can produce, by mitotic division, daughter cells that can differentiate (specialise for different functions)
All multicellular organisms begin as an undifferentiated cell.
The zygote divides by mitosis and soon the cells begin to differentiate (specialise)
What does pluripotent mean?
Embryonic stem cells are pluripotent (can form any type of cell/tissue, except for the placenta)
Pluripotent means a cell can specialise to any form of tissue except for the placenta.
What does multipotent mean?
Bone marrow stem cells are multipotent (can form several types of cell)
They are more limited than pluripotent cells.
What are the four types of tissue?
Connective tissue, epithelial tissue, muscle tissue, nervous tissue.
These tissue types make up the entire human body.
What is connective tissue?
a diverse and widely distributed type of tissue in the body that provides structural support, connects and binds different tissues and organs, and plays a key role in various physiological processes.
What is epithelial tissue?
a type of tissue that forms the surfaces of body structures, lining organs, cavities, and passageways, and serves as a protective barrier while also facilitating absorption, secretion, and sensory functions.
What is muscle tissue?
a specialized type of tissue in the body composed of cells (muscle fibers) that contract and generate force when stimulated, allowing for movement, stability, and various physiological functions.
What is nervous tissue?
a complex tissue in the body consisting of specialized cells called neurons that transmit electrical and chemical signals, enabling communication and coordination within the nervous system and facilitating sensory perception, motor control, and cognitive functions.
What are organs?
Organs are made up of different tissues to perform specific functions.
For example:
Gastrointestinal tract contains:
- Connective tissue between folds of intestine
- Muscle tissue around tubes
- Epithelial tissue lining tract
What are systems?
Organs are arranged in systems so that they work together in a coordinated manner.
Organs can play a role in more than one system
For example:
The liver synthesises and secretes bile to help digest lipids (digestive system)
The liver synthesises and secretes hormones (endocrine system)
How are cells different if they contain the same DNA?
Every cell contains identical DNA/genes
So, how can cells differentiate to have such different structures and functions?
Different cells have different genes that are either expressed (turned on) or not expressed (turned off)
What is a function of stem cells?
In multicellular bodies, stem cells are constantly dividing to grow, or replace old and damaged cells
