Module 1: Cellular environment Flashcards
What are the 4 levels of organisation?
Cells, tissues, organs and systems
Define homeostasis
the state of steady internal, physical, chemical, and social conditions maintained by living systems. for the body to be in homeostasis, each cell has to be in the same state of homeostasis
Name the 5 plasma membrane functions
Structure (maintenance of fluid and electrolyte balance)
Protection (barrier to toxic molecules)
Cell activation (antigen-activating antibody synthesis)
Transport (diffusion/osmosis)
Cell-cell interactions (cell communication and attachment
- ALL HAVE THE COMMON GOAL OF MAINTAINING HOMEOSTASIS
Explain the 3 types of cellular communication
- Contact signaling via gap junctions (when cells are next to one another, ex sodium potassium ions)
- Contact signaling by plasma membrane-bound receptors (cells can secrete signaling molecules that float around and then be captured or bind to receptors located on the receiving cells. ex: neurons releasing neurotransmitters to communicate with other neurons)
- Remote signaling by secreted molecules (carrier proteins will transport the signaling molecule through the bloodstream to the target cell, the signaling molecule will go withing the receiving cells and interact with the nucleus)
Explain the different modes of chemical signalling
- Autocrine (secreting cell targets itself)
- Paracrine (secreting cells communicate short distance with target cells, can be with neurotransmitters too)
- Hormonal (hormones go through the bloodstream to get to the target cells)
What is signal transduction?
Translating a form of energy into another so that it induces a change in the behavior of a cell
What are the 3 ion channels cellular receptors?
- Ligand-gated (ex GABA or Glutamate. open when they bind into them)
- Voltage-gated (ex neurons. commonly found onto neurons or muscle tissues. when there’s a switch in sodium-potassium levels, the voltage is changed within the internal compartment of the cells, which causes the receptor to open)
- Mechanically-gated (ex touch. the physical energy or pressure exerted open and close different types of ion channels)
True or false, active transport requires energy.
True! A movement against the chemical gradient requires ATP. Sodium-potassium pump is the most important active transport pump.
What is facilitated diffusion used for?
for molecules like charged sodium,charged potassium or glucose, because they cannot pass through the membrane. they need a protein to bypass it. it requires no energy because it follows the concentration gradient
What are the causes of edema?
- Increased hydrostatic pressure (ex hypertension)
- Increased membrane permeability (ex trauma, vasodilation)
- Decreased oncotic pressure (ex liver or kidney failure)
- Increased lymphatic obstruction (ex tumors)
What are the adaptations of the cells to injury?
- Atrophy (decrease in size and number)
- Hypertrophy (increase in size)
- Hyperplasia (increase in number of cells)
- Metaplasia (change in cell type)
- Dysplasia (changing into a dysfunctional cell that does not exist. abnormal organization, is not a true adaptation)
What are the physiologic and pathologic reasons for cell atrophy?
Phys: during early development (cells between fingers
Path: -decreased workload, nutrition or stimulation
What are the physiologic and pathologic reasons for cell hypertrophy?
Phys: adaptive size increase to achieve a new homeostasis state (ex weightlifting leads to muscle hypertrophy)
Path: compensatory size increase secondary to a problem to try to restore homeostasis (ex cardiac hypertrophy secondary to heart failure)
What are the 3 types of hyperplasia?
- Compensatory hyperplasia (ex liver regeneration, wound healing, callus, etc)
- Hormonal hyperplasia (ex enlargement of uterus or breasts)
- Pathologic hyperplasia (ex secondary to hormonal imbalance or excessive growth factors stimulation)
What are the 4 themes of cell injury?
- Decrease in ATP synthesis
- Loss of cell membrane in integrity
- Decrease in O2 and increase in free radicals
- Increase in intracellular Ca2+
