Human Bio Flashcards
Cell Membrane:
The outer boundary of the cell that separates it from neighboring cells and from the external environment. Determines which substance gets in and out.
Golgi Body:
Flattened membranous bags stacked on top of each other. They modify proteins and package them in vesicles for secretion from the cell.
Vesicle:
A membrane bound sac that transports materials into, out or within the cell.
Mitochondria:
Spherical and elongated structure spread through the cytoplasm. Mitochondria release energy for the cell through the process of respiration.
Nucleus:
Usually ovoid or spherical. Contains the genetic material, mostly DNA, separated from the cytoplasm by a nuclear membrane. It has nuclear pores where large molecules can pass through.
Nucleolus:
Is composed mainly of RNA. The DNA and nucleolus are suspended in a jelly-like nucleoplasm.
Cytoplasm:
Thick fluid within the cell membrane and all the structure suspended in it. Cytosol is the liquid part of the cytoplasm. 75-90% water.
Centrioles:
A pair of cylindrical structures usually located near the nucleus, involved in the reproduction of the cell.
Endoplasmic Reticulum:
Pairs of parallel membranes extending through the cytoplasm and connecting the cell membrane with the nuclear membrane. Provides a surface on which chemical reactions can occur. The channels between the paired membranes are used for storage or to transport material. Most ER have ribosomes attached while some don’t.
Ribosomes:
Very small and spherical. Amino acids are joined together at the ribosomes to make proteins.
Cytoskeleton:
Consist of microfilaments and microtubules that give the cell its shape and assist the movement of the materials.
Lysosomes:
Small spherical that contain enzymes able to break down proteins, lipids, nucleic acids and some carbohydrates. Lysosomes break down materials that are taken into the cell or break down worn out organelles.
Inclusion:
Substances that are not part of the cell structure but are found in the cytoplasm.
Types of Transport through the cell membrane:
1.Simple diffusion
2.Faciliated transport
3.Vesicular Transport
What is passive transport?
Passive transport does not require any energy and the substances move with the concentration gradient.
What is active transport?
Active transport does require energy and substances move against the concentration gradient.
Passive Transport simple diffusion:
The spreading out of particles is brought out due to more collisions happening with the particles at high concentrations.
This forces them to move away from each other into areas with low concentration where they experience less collisions.
Diffusion
The spreading out of particles from areas of high concentration to areas of low concentration resulting in even distribution.
Simple Diffusion: Concertation Gradient
The difference in concentration that brings about diffusion is known as concentration gradient. The greater the difference between the two concentrations faster the rate of diffusion.
Passive Transport Facilitated Diffusion:
Definition of Diffusion but occurs through a channel protein. Generally used for water molecules and ions as they are polar molecules. Polar molecules cannot pass through the phospholipid bilayer.
Passive Transport Osmosis
Osmosis: The diffusion of a solvent(water) through a differentially (semi) permeable membrane.
The solvent is able to move through the membrane but the solute is not able to fit through.
The only way to reach equilibrium is for the solvent to move.
Passive Transport Osmosis and Tonicity.
Tonicity is the concentration of a solution as compared to another solution.
Isotonic: Extracellular and intracellular ionic concentration equal.
Hypotonic: Extracellular ionic concentration is less than intracellular
Hypertonic: Extracellular ionic concentration is more than intracellular.
Active Transport
Definition of Diffusion + Occurs predominantly through carrier proteins and requires energy. Useful when substances need to move against the concentration gradient such as sodium to maintain the osmotic pressure.
Vesicular Endocytosis
The taking in of solids or liquids through vesicles.
Cell membrane folds around the substance until it is completely enclosed.
Vesicle then pinches off within the cytoplasm.
Pinocytosis - taking in liquids(cell drinking)
Phagocytosis - taking in solid particles.
Exocytosis
Exocytosis is when a vesicle formed inside the cytoplasm migrates outside of the cell.
1.Vesicle forms around the substance to be removed.
2.Migrates to and fuses with the membrane.
3. Contents of the vesicles are pushed into the extracellular fluid.
Structure of Cell Membrane
The main structure of of the cell membrane is composed of phospholipid molecules, which are lipids molecules containing a phosphate group.
The phospholipids are arranged in two layers, known as a bilayer. Each phospholipid molecule has a head that is hydrophilic(water loving) and a tail that is hydrophobic(water hating).
The phospholipids are arranged in the two layers with their heads on the outside and tails on the inside.
Tissue Type - Epithelium Function:
It Protects us from the outside world - skin
Absorbs - stomach and intestinal lining gut
Filters - kidney
Secretes - forms gland
Characteristics of Epithelium:
- Closely attached to each other forming a protective barrier.
- Always has 1 free(apical) surface open to the outside the body or inside(cavity) an internal organ.
3.Always had one fixed(basal) section attached to underlying connective tissue.
4.Have no blood vessels but can soak up nutrients from blood vessels in connective tissue underneath.
5.Can have lots of nerve in it.
6.Very good at regenerating it self.
Classification Types of Epithelium:
By Shape:
1.Squamous - flat and scale like
2.Cuboidal - as tall as they are wide.
3.Columnar - Tall, column-shaped.
By Cell Arrangement:
1.Simple epithelium - single layer of cells usually for absorption and filtration.
2.Stratified Epithelium - stacked up cell layers (Protection from abrosion(rubbing-mouth, skin).
Connective Issue:
1) Wraps around and cushions and protects organs.
2) Store nutrients
3) Internal support for organs.
4)As tendons and ligaments protect joints and attached muscles to bone and each other.
5) Runs through organ capsules and in deep layers of skin giving strength.
3 Elements of connective Tissue:
1. Ground Substances - gel around cells and fibers
2.Fibers - provide strength, elasticity and support
3.Cells
Two kinds of Connective Tissue
1) Areolar Connective Tissue - Cushion around organs, loose arrangement of cells and fibers.
2) Adipose Tissue - storehouse for nutrients, packed with cells and blood vessels.
3)Reticular connective tissue - internal supporting framework of some organs, delicate network of forces and cells.
Dense Connective Tissue:
1) Dense regular connective tissue - tendons and ligaments, regularly arranged bundles packed with fibers running some way for strength in one direction.
2) Dense irregular connective tissue - skin organ capsules, irregular arranged bundles packed with fibers for strength in all directions.
Special Connectives Tissues and bones:
-Provides strength with flexibility while resisting wear.
-Cushions and shock absorbs where bones meet.
Bone:
1.Provides framework and strength for body.
2.Allows movement
3.Stores calcium and contains blood forming cells.
Nervous Tissue:
1.Conducts impulses to and form body organs via neurons.
-Brain
-Spinal Cord
-Nerves
Muscle Tissue:
1) Responsible for body movement
2) Moves blood, food, waste through body’s organs
3) Responsible for mechanical digestions.
3 Types of Muscle Tissue:
1.Smooth muscle - organ walls and blood vessels walls. Involuntary spindle shaped cells for pushing things through organs.
2.Skeletal muscle - large body muscles, voluntary striated muscles packed in bundles and attached to bones for movement.
3.Cardiac muscle - heart wall, involuntary, striated muscle with intercalated discs connecting cells for synchronized contractions during heat beat.
