Chapter 3: The cells, tissues and organization of the body Flashcards
What are cells?
the body’s smallest functional units
Cells are group together to form?
tissues-each of which has a specialized function, e.g., blood, muscle, bone.
Tissues are grouped together to form?
organs, e.g., the heart, stomach, and brain.
organs are grouped together to form?
systems, each of which performs a particular function that maintains homeostasis and contributes to the health of the individual
what are the two types of cells?
Prokaryotes
Eukaryotes
Characteristic of a cell?
Cells provide structure and support to the body of an organism.
The nucleus
(major organelle) holds genetic information necessary for reproduction and cell growth.
Mitochondria
a double membrane-bound organelle is mainly responsible for the energy transactions vital for the survival of the cell.
Lysosomes
digest unwanted materials in the cell.
Endoplasmic reticulum
plays a significant role in the internal organization of the cell by synthesizing selective molecules and processing, directing, and sorting them to their appropriate locations.
plasma membrane
The plasma membrane of a cell is a network of lipids and proteins that forms the boundary between a cell’s contents and the outside of the cell.
The main function of the plasma membrane is to protect the cell from its surrounding environment.
membrane proteins
are the binding proteins that mediate conduction of ions or molecules into and out of the cell membrane.
Chromosome
is a string of DNA wrapped around associated proteins that give the connected nucleic acid bases a structure.
ribosomes
are the sites at which information carried in the genetic code is converted into protein molecules.
Goli apparatus
is an organelle in eukaryotic organisms that moves molecules from the endoplasmic reticulum to their destination.
Lysosomes
are small membranous vesicles pinched off from the Golgi apparatus.
Cytoskeleton
a microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence.
microfilaments
These are the smallest fibers. They provide structural support, maintain the characteristic shape of the cell and permit contraction, e.g., actin in muscle cells.
microtubules
These are larger contractile protein fibers that are involved in the movement of:
- organelles within the cell
- chromosomes during cell division
- cell extensions
Interphase
the resting phase between successive mitotic divisions of a cell, or between the first and second divisions of meiosis
mitosis
a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.
Prophase
the first stage of cell division, before metaphase, during which the chromosomes become visible as paired chromatids and the nuclear envelope disappears. The first prophase of meiosis includes the reduction division.
metaphase
the second stage of cell division, between prophase and anaphase, during which the chromosomes become attached to the spindle fibers.
anaphase
the stage of meiotic or mitotic cell division in which the chromosomes move away from one another to opposite poles of the spindle.
telophase
the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.
passive transport
the movement of substances (as by diffusion) across a cell membrane without the expenditure of energy.
diffusion
is the net passive movement of molecules or particles from regions of higher to regions of lower concentration.
Osmosis
is the passive movement of water down its concentration gradient towards equilibrium across a semipermeable membrane.
Active transport
This is the transport of substances up their concentration gradient (uphill), i.e., from a lower to a higher concentration
Sodium-Potassium Pump
the process of moving sodium and potassium ions across the cell membrane is an active transport process involving the hydrolysis of ATP to provide the necessary energy.
Bulk Transport
Transfer of particles too large to cross cell membranes occurs by pinocytosis (‘cell drinking) or phagocytosis (‘cell eating).
Tissues
Tissues consist of large numbers of the same type of cells and are classified according to the size, shape, and functions of their constituent cells.
Epithelial Tissue
Forms the outer covering of the skin and lines the body cavity.
The structure of epithelium is closely related to its functions, which include:
-protection of underlying structures from, for example, dehydration, chemical, and mechanical damage
-secretion
-absorption
Simple epithelium
has only one cell layer where every cell is in direct contact with the underlying basement membrane.
Squamous epithelium
This is composed of a single layer of flattened cells. The cells fit closely together like flat stones, forming a thin and very smooth membrane across which diffusion occurs easily.
cuboidal epithelium
Simple cuboidal epithelium is a type of epithelium that consists of a single layer of cuboidal (cube-like) cells. These cuboidal cells have large, spherical, and central nuclei. … On these surfaces, the cells perform secretion and absorption.