CELLS AND TISSUES Flashcards by hhshsjwy, pmmmamnhwg

• Structural units of all living things
• Human body contains 50-100 trillion of _____

CELLS

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Discovered by ______ and named then as “cells”

ROBERT HOOKE

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3 main regions of cell

NUCLEUS
CYTOPLASM
PLASMA MEMBRANE

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Control center of the cell and contains genetic material (DNA)

NUCLEUS

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• Barrier of the nucleus
• Consists of a selectively permeable,
double phospholipid membrane
• Contains nuclear pores that allow for exchange of material with the rest of the cell

Nuclear Membrane

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3 regions of nucleus

• Nuclear membrane
• Nucleolus
• Chromatin

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Cells are not all the same in terms of:

SIZE
SHAPE
FUNCTION

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containing the nucleoli and chromatin – fluid similar to
cytoplasm

NUCLEOPLASM

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Sites of ribosome production and partial assembly

NUCLEOLI

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• Composed of unwound DNA and protein – used for making proteins
• Scattered throughout the nucleus
• condenses to form chromosomes when the cell divides

CHROMATIN

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• Barrier for cell contents
• Semi-permeable, Double phospholipid layer

PLASMA MEMBRANE

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plasma membrane consists of Hydrophilic heads which means ______ and Hydrophobic tail means _______

Hydrophilic heads – water loving Hydrophobic tails – water fearing

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Other materials in plasma membrane

• Protein – receptors, cell recognition and communication, channels for transport
• Cholesterol – keep membrane fluid and stable
• Glycoproteins – receptors, cell-to-cell interactions

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plasma membrane specializations

MICROVILLI
MEMBRANE JUNCTIONS

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Finger-like projections that increase surface area for absorption

MICROVILLI

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Tight junctions – impermeable, leakproof sheets
• Desmosomes – anchorings that prevent cells from being separated
• Gap junctions – allow communication between cells through connexons that
span the two cell membranes

MEMBRANE JUNCTIONS

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Material outside the nucleus and inside the plasma membrane

CYTOPLASM

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Fluid containing nutrients dissolved in water that suspends other elements

CYTOSOL

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Metabolic machinery of the cell

ORGANELLES

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Non-functioning units – stored nutrients such as fat droplets, glycogen granules, pigments, and mucus

INCLUSIONS

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Cytoplasmic Organelles

MITOCHONDRIA
RIBOSOMES
ENDOPLASMIC RETICULUM
GOLDI APPARATUS
LYSOSOMES
PEROXISOMES
CYTOSKELETON
CENTRIOLES

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• “Powerhouses” of the cell
• Change shape continuously
• Has a double membrane and had its own DNA
• Carry out reactions where oxygen is used to break down food – cell respiration
• Provides ATP for cellular energy

MITOCHONDRIA

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• Made of protein and RNA
• Sites of protein synthesis

RIBOSOMES

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Ribosomes can be found at two locations:

Free in the cytoplasm
Attached to rough endoplasmic reticulum

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Fluid-filled tubules for carrying substances

ENDOPLASMIC RETICULUM

a type of ER that is Studded with ribosomes and a Site where building materials of cellular membrane are formed

ROUGH ENDOPLASMIC RETICULUM

a type of ER that Functions in cholesterol synthesis and breakdown, fat metabolism, and detoxification of drugs

SMOOTH ENDOPLASMIC RETICULUM

• Modifies and packages proteins • Produces different types of packages • Secretory vesicles – contain proteins for export • Cell membrane components to be added to the plasma membrane • Lysosomes – contain hydrolytic enzymes

GOLGI APPARATUS

Contain enzymes that digest non-usable materials within the cell such as old organelles as well as bacteria and viruses

LYSOSOMES

• Membranous sacs of oxidase enzymes • Detoxify harmful substances using O2 • Break down free radicals (highly reactive chemicals with free electrons) • Replicate by pinching in half

PEROXISOMES

• Network of protein structures that extend throughout the cytoplasm • Provides the cell with an internal framework • Determines cell shape, supports organelles, provides path for intracellular transport, involved in cell movement

PEROXISOMES

3 Different Types of Cytoskeleton

MICROFILAMENTS INTERMEDIATE FILAMENTS MICROTOBULES

cell motility and changed in cell shape – actin and myosin

MICROFILAMENTS

help form desmosomes and internal guy wires

INTERMEDIATE FILAMENTS

determine overall shape of a cell and location of organelles

MICROTOBULES

• Rod-shaped bodies made of microtubules that lie at right angles to each other and near the nucleus • Direct formation of mitotic spindle during cell division

CENTRIOLES

• Not found in all cells • Used for movement

CILIA AND FLAGELLA

moves materials across the cell surface – usually short and many

CILIA

propels the cell – usually long and few in number

FLAGELLUM

homogeneous mixture of two or more components (solute and solvent)

SOLUTION

dissolving medium

SOLVENT

components in smaller quantities within a solution

SOLUTES

nucleoplasm and cytosol

INTRACELLULAR FLUID

fluid on the exterior of the cell

INTERSTITIAL FLUID

movement of substance into and out of the cell

MEMBRANE TRANSPORT

two basic methods of membrane transport

1. Passive Transport 2. Active Transport

a method of transport where no energy us requires

Passive Transport

a method of transport where the cell must provide metabolic energy

Active Transport

Selectively permeable

membranes

allows some materials to pass while excluding others

PLASMA MEMBRANE

PASSIVE TRANSPORT PROCESSES

1. Diffusion 2. Filtration

Movement is from high concentration to low concentration, or down a concentration gradient

Diffusion

Movement is due to kinetic energy in the molecules and affected by size and temperature

Diffusion

Particles tend to distribute themselves evenly within a solution

DIFFUSION

Types of Diffusion

1. Simple Diffusion 2. Osmosis 3. Facilitated Diffusion

• Passive diffusion • Unassisted process • Solutes are lipid-soluble materials or small enough to pass through membrane pores

Simple diffusion

• simple diffusion of water • Highly polar water easily crosses the plasma membrane • Occurs all the time

Osmosis

• Substances require a protein carrier for passive transport • Still moving down concentration gradient and so no energy is needed

Facilitated Diffusion

• Water and solutes are forced through a membrane by fluid, or hydrostatic pressure • pressure gradient must exist • Solute-containing fluid is pushed from a high pressure area to a lower pressure area

Filtration

Transport substances that are unable to pass by diffusion

• They may be too large • They may not be able to dissolve in the fat core of the membrane • They may have to move against a concentration gradient

Two common forms of active transport

• Solute pumping • Bulk transport

•Amino acids, some sugars and ions are transported by solute pumps • ATP energizes protein carriers, and in most cases, moves substances against concentration gradients • Can transport different molecules different directions such as the sodium-potassium pump

SOLUTE PUMPING

• Moves materials out of the cell • Material is carried in a membranous vesicle •Vesicle migrates to plasma membrane • Vesicle combines with plasma membrane • Material is emptied to the outside

BULK TRANSPORT (Exocytosis)

• Extracellular substances are engulfed by being enclosed in a membranous vescicle

BULK TRANSPORT (endocytosis)

Types of endocytosis

• Phagocytosis - cell eating • Pinocytosis - cell drinking

Series of changes a cell goes through from the time it is formed until it divides

CELL LIFE CYCLE

two(2) major periods of cells

1. Interphase – metabolic phase 2. Cell division

• Longest phase where the cell grows • Cell carries on metabolic processes

INTERPHASE

• Cell replicates itself • Function is to produce more cells for growth and repair processes

Cell division

• Genetic material duplicated and readies a cell for division into two cells • Occurs toward the end of interphase • DNA uncoils and each side serves as a template

DNA REPLICATION

EVENTS OF CELL DIVISION

1. Mitosis 2. Cytokines

• Division of the nucleus • Results in the formation of two daughter nuclei

Mitosis

• Division of the cytoplasm • Begins when mitosis is near completion • Results in the formation of two daughter cells

Cytokinesis

stages of mitosis

INTERPHASE PROPHASE METAPHASE ANAPHASE TELOPHASE

• No cell division occurs • The cell carries out normal metabolic activity and growth

INTERPHASE

• First part of cell division • Centromeres migrate to the poles and direct the assembly of the mitotic spindle • Chromosomes form

PROPHASE

Spindle from centromeres are attached to chromosomes that are aligned in the center of the cell

METAPHASE

• Daughter chromosomes are pulled toward the poles • The cell begins to elongate

ANAPHASE

• Daughter nuclei begin forming • A cleavage furrow (for cell division) begins to form and finished dividing the cell into two by the end of cytokinesis • Everything from prophase is reversed

TELOPHASE

DNA segment that carries a blueprint for building one protein

GENE

FUNCTION OF PROTEIN (2)

• Building materials for cells • Act as enzymes (biological catalysts)

essential for protein synthesis

RNA

ROLES OF RNA

1. Transfer RNA (tRNA) • Transfers appropriate amino acids to the ribosome for building the protein 2. Ribosomal RNA (rRNA) • Helps form the ribosomes along with proteins where proteins are built 3. Messenger (mRNA) • Carries the instructions for building a protein from the nucleus to the ribosome

Transfers appropriate amino acids to the ribosome for building the protein

Transfer RNA (tRNA)

Helps form the ribosomes along with proteins where proteins are built

Ribosomal RNA (rRNA)

Carries the instructions for building a protein from the nucleus to the ribosome

Messenger (mRNA)

Transfer of information from DNA’s base sequence to the complimentary base sequence of mRNA – switching T for U

TRANSCRIPTION

Base sequence of mRNA is translated to an amino acid sequence based on codon/anticodon complements

TRANSLATION

building blocks of proteins

AMINO ACID

Four primary types of body tissues

• Epithelium (for covering) • Connective tissue (for support) • Nervous tissue (for control) • Muscle (for movement)

Found in different areas • Body coverings • Body linings • Glandular tissue

EPITHELIAL TISSUE

Functions of Epithelial Tissue

• Protection • Absorption • Filtration • Secretion

have no blood supply

Avascular

cell layers

• Simple (one layer) • Stratified (more than one layer)

Shape of cells

• Squamous (flattened) • Cuboidal (cube-shaped) • Columnar (column-like)

• Single layer of flat cells • Usually forms membranes where filtration or exchange occurs

Simple Squamous

Function of Simple Squamous

• Lines body cavities – serous membranes • Lines lungs and capillaries

• Single layer of cube- like cells • Common in glands and their ducts • Forms walls of kidney tubules • Covers the ovaries

Simple Cubodial

• Single layer of tall cells that fit closely together • Often includes goblet cells, which produce mucus • Lines digestive tract

Simple Columnar

mucous membranes line body cavities open to the body exterior

Mucosae

• Single layer, but some cells are shorter than others • Often looks like a double cell layer • Sometimes ciliated, such as in the respiratory tract • May function in absorption or secretion

Pseudostratified columnar

• Cells at the free edge are flattened while cells close to the basement membrane are cuboidal or columnar • Found as a protective covering where friction is common Locations: • Skin • Mouth • Esophagus

Stratified squamous

• Surface cells are columnar, cells underneath vary in size and shape

Stratified columnar

• Rare in human body • Found mainly in ducts of large glands

Stratified cuboidal and columnar

• Shape of cells depends upon the amount of stretching • Cells of the basal layer are cuboidal or columnar while those at the free surface vary • Lines organs of the urinary system

Transitional epithelium

one or more cells that secretes a particular product – a secretion, which contains protein molecules in an aqueous fluid

GLAND

Two major gland types

1. Endocrine gland 2. Exocrine gland

• Ductless • Secretions are hormones – diffuse into blood

ENDOCRINE GLAND

• Empty through ducts to the epithelial surface • Include sweat and oil glands

EXOCRINE GLAND

• Found everywhere in the body • Includes the most abundant and widely distributed tissues

Connective Tissue

Functions of Connective Tissue

• Binds body tissues together • Supports the body • Provides protection

Non-living material that surrounds living cells

Extracellular matrix

Two main elements

1. Ground substance - mostly water along with adhesion proteins and polysaccharide molecules 2. Fibers - Produced by the cells

Three types of Fibers

• Collagen fibers • Elastic fibers • Reticular fibers

Types of Connective Tissues (6)

1. Bone (osseous tissue) 2. Hyaline cartilage 3. Fibrocartilage 4. Elastic cartilage 5. Dense connective tissue

Used to protect and support the body Composed of: • Bone cells in lacunae (cavities) • Hard matrix of calcium salts • Large numbers of collagen fibers

Bone (osseous tissue)

• Most common cartilage • Abundant collagen fibers • Rubbery matrix • Entire fetal skeleton is hyaline cartilage

Hyaline cartilage

• Highly compressible • Example: forms cushion-like discs between vertebrae

Fibrocartilage

• Provides elasticity • Example: supports the external ear

Elastic cartilage

• Main matrix element is collagen fibers • Crowed between the collagen fibers are rows of cells called fibroblasts

Dense connective tissue

• Most widely distributed connective tissue • Soft, pliable tissue • Functions as universal packing tissue and connective tissue glue • Contains all fiber types • Can soak up excess fluid

Areolar connective tissue

• Matrix is an areolar tissue in which fat globules predominate • Many cells contain large lipid deposits Functions • Insulates the body • Protects some organs • Serves as a site of fuel storage

Adipose tissue

• Delicate network of interwoven fibers • Forms stroma (internal supporting network) of lymphoid organs • Lymph nodes • Spleen • Bone marrow

Reticular connective tissue

• Blood cells surrounded by fluid matrix • Fibers are visible during clotting • Functions as the transport vehicle for materials

Blood

Function is to produce movement by contracting or shortening

MUSCLE TISSUE

Three types of Muscle Tissue

• Skeletal muscle • Cardiac muscle • Smooth muscle

• Can be controlled voluntarily • Cells attach to connective tissue • Cells are striated • Cells have more than one nucleus

Skeletal muscle

• Found only in the heart • Function is to pump blood (involuntary) • Cells attached to other cardiac muscle cells at intercalated disks • Cells are striated • One nucleus per cell

Cardiac muscle

• Involuntary muscle • Surrounds hollow organs • Attached to other smooth muscle cells • No visible striations • One nucleus per cell •Spindle shaped

Smooth muscle – visceral muscle

• Neurons and nerve supporting cells (those that insulate, support, and protect neurons) • Function is to receive and send impulses to other areas of the body • Irritability •Conductivity

Nervous Tissue

Tissue Repair (wound Healing)

• Regeneration • Fibrosis • Determination of method

Replacement of destroyed tissue by the same kind of cells

Regeneration

Repair by dense fibrous connective tissue (scar tissue)

Fibrosis

- Type of tissue damaged - Severity of the injury

Determination of method