NUR 3125 - PATHO - Cells and Tissues

Nucleus

holds DNA

seperates DNA from cytoplasm with nuclear membrane

can still communicate with cytoplasm due to pores that take molecules to cytoplasm

RNA

made through transcription

messenger

sent from nucleus → cytoplasm

takes information about DNA to cytoplasm in order to make proteins

Ribosomes

protein synthesis

where protein is made

free in cytoplasm, but attached to rough ER

(what makes rough ER, rough)

Endoplasmic Reticulum

synthesis of proteins & lipids

Transport of proteins

Golgi Apparatus

processing & packaging of proteins

Lysosomes

digest cellular substances

Mitochondria

ATP energy; powerhouse of cell

ATP → needed to make energy

that allows cell to work

Cellular respiration → oxygen & nutrients needed to make ATP

Cytoplasm

fluid-like; everything in between where we have organelles

Cytoskeleton

bones & muscles of cell

Differentiation/ Maturation

expression of different proteins depending on tissue; different function

8 cellular functions

1. Movement → Muscle cells

- Generate forces

2. Conductivity → Nerve Cells

- Produce action/electrical potential

- Send signals from neuron to neuron to muscle

3. Secretion → Mucous Gland Cells

4. Excretion → All Cells

- can rid themselves of waste products like CO2

5. Metabolic Absorption → All Cells

- absorption & use of nutrients

6. Respiration → All Cells

- transformation of nutrients into energy (ATP)

- Excretes CO2

7. Reproduction → All Cells

- can grow tissue

- can replace cells

8. Communication → All Cells

- vital to survive

Cell Energy Metabolism

chemical tasks of maintaining cellular functions

Anabolism

builds up; Energy-using process

-EXAMPLE: Building blocks of proteins → amino acids (need anabolism)

Catabolism

breaks down; Energy- releasing process

-EXAMPLE: break down of carbohydrates, fats, & proteins into energy needed for cell function (need catabolism)

Aerobic Metabolism

presence of oxygen

Anaerobic Metabolism

lack of oxygen

Passive transport

NO ENERGY NEEDED

includes 2 types of diffusion:

1. facilitated

2. passive

Diffusion

movement of solutes from area of GREATER concentration → area of LESSER concentration

ALWAYS MEANS DOWN THE CONCENTRATION GRADIENT

DOES NOT NEED ENERGY

- EXAMPLE: teacher puts perfume on → it hits first row of students first, last row of students last

Facilitated Diffusion

membrane protein facilitated diffusion

-EXAMPLE: In plasma membrane, with a bilipid layer, there is a protein that has a tube-like "pocket" in the middle, going from top to bottom. The glucose molecule can use this "pocket" in the protein to diffuse (go through) it.

Passive Diffusion

substance diffuses across plasma membrane

NO PROTEIN INVOLVED

only few molecules can pass through

- EXAMPLE: O2, alcohol, CO2

Osmosis

movement of water down a concentration gradient

occurs across semipermeable membrane

from region of HIGHER water concentration to one of LOWER concentration

Active Transport

ALWAYS NEEDS ENERGY AND A MEMBRANE PROTEIN

AGAINST ITS CONCENTRATION GRADIENT!

- meaning UP

transport of molecules across plasma membrane

- from region of LOWER concentration to one of HIGHER concentration

-EXAMPLE: going from waiting outside of a subway to hopping onto a packed one.

ATPase Pump

VERY IMPORTANT TRANSPORTER IN BODY

Na + K + ATPase pump

helps maintain gradient of sodium & potassium in body

uses ATP → move sodium out & potassium in

Epithelial Tissue

covers most of internal & external body surfaces

- Simple squamous epithelium

- Transitional epithelium

- Stratified squamous epithelium

- Simple cuboidal epithelium

- Simple columnar epithelium

- Stratified columnar epithelium

Connective Tissue

binds tissue to organs together

- Adipose

- Cartilage

- Bone

- Blood

Nerve Tissue

specialized cells

- Neurons

- Glia

Muscle Tissue

composed of myocytes

- Striated

- Cardiac

- Smooth

Atrophy

decrease in cellular size

- EXAMPLE: taking a cast off after 4 weeks to find that the casted arm is smaller than the uncasted arm; cells that are making muscles in arm get smaller because of the lack of use

Hypertrophy

increase in cell size

(due to mechanical stimuli)

DOES NOT MEAN THERE ARE MORE CELLS

CELLS ARE GETTING BIGGER

-EXAMPLE: the more you hit arms at the gym, the bigger the muscles gets

Hyperplasia

increase in # of cells

CELLS DO NOT GET BIGGER

THERE IS MORE CELLS

-EXAMPLE: a liver that regenerates by dividing its cells fast; you can give different parts of a liver to different people because the cells divide fast and will regenerate in a timely matter

Metaplasia

replacement of one mature cell by another

- EXAMPLE: too much smoking causes columnar ciliated epithelial cells to get replaced by stratified squamous epithelial cells; bad news is that the new squamous epithelial cells will NOT protect as much as the initial columnar ciliated cells. IF you stop smoking, the protective columnar ciliated epithelial cells will regenerate and allow for the extra layer of protection

Dysplasia

abnormal development of growth of cells

(abnormal changes in size, shape, and organization of mature cell)

not a true adaptive change; can SOMETIMES go back to its normal size

does not indicate cancer, but may progress into cancer

Tumor

overgrow of cells

Benign Tumor

not usually cancerous

stays in place; does not invade other sites of body

grows slowly

needs to be removed regardless (in most cases)

may progress to cancer

(benign → malignant)

Malignant Tumor

cancerous and can spread cancer cells

rapid growth rates with very small alterations

spread far beyond tissue of origin (metastasis)

- through body, blood, or lymphatic system

Carcinoma in Situ (CIS)

group of abnormal cells that have NOT spread from location where they first formed

don't always move

may spread into normal tissue and become cancer

early-stage of cancer

Cell Injuries

1. Physical Agents

- contusions

- lacerations

- fractures

- incised wounds

- stab wounds

- puncture wounds

2. Radiation Injury

3. Chemical Injury

- over-the-counter drugs

- prescribed drugs

4. Nutritional Imbalances

- low intake of food

- high intake of food

5. Hypoxic Injury

- MOST COMMON CAUSE OF CELLULAR INJURY

- low oxygen

6. Free Radical Injury

- oxidative stress due to excessive reaction to O2 species (ROS)

Apoptosis

programmed cell death; cell KNOWS it has to die → self-destruction of cell

- elimiates aged/injured cell

CAN BE PHYSIOLOGIC & PATHOLOGIC

quiet way of dying; no one around will notice

-EXAMPLE: normal cell knows its time to die → there will be changes in cytoplasm & nucleus of cell → there will be membrane blebs & apoptotic bodies → cells will die & break off into small fragments of cell little by little (phagocytosis)

Physiologic Process

natural destruction of cells

destruction of cells during embryonic process - when baby is born without specific tissues

endometrial cells during menses

- endometrial cells keep growing & growing (excess) → menses comes & endometrial cells self-destruct

breast tissue regression after breast feeding

Pathologic Process

dysregulated apoptosis → can be pathologic if too much or too little

autoimmune disorders

carcinogenesis → survival of abnormal cells

too much apoptosis?

- neurological disorders

too little apoptosis?

- cells that should be dying because DNA is no longer normal, but are still surviving

Necrosis

death of cell that should not be dying → cell is missing nutrients, oxygen

cell death in organ/tissue that should still be alive

- due to environmental changes

ALWAYS PATHOLOGICAL

INVOLVES INFLAMMATION

not quiet, everyone around will notice due to the active inflammation

-EXAMPLE: normal cell is not supposed to be dying, but stopped receiving nutrients → also has membrane blebs → will be an explosion of the cell → breakdown of plasma membrane, organelles, and nucleus → there will be leaking content that will lead to inflammation

Chromosomes

chromatin condensed

23 pairs in every single cell in humans

- except gametes:

- eggs from females have 23

individual chromosomes

- sperm from males have 23

individual chromosomes

the form in which DNA is structured in nucleus of cell

come together to form pair

- half mother

-half father

how many chromosomes are inherited?

Female (egg 23 chromosomes, 22 + X)

+

Male (sperm 23 chromosomes, 22 + X or Y)

=

Zygote 46 chromosomes

Autosomes

any chromosome that is not a sex chromosome

22 pairs of chromosomes

(or 44 individual chromosomes)

Sex Chromosomes

chromosomes that determine the sex of an individual

X & X pair: FEMALE

X & Y pair: MALE

1 pair

(or 2 individual chromosomes)

Diploids

two copies of each chromosome and two copies of each gene

PAIRS

23 pairs of chromosomes

Haploids

a cell with one copy of each chromosome

INDIVIDUALS

ONLY 23 chromosomes

Chromatin

clusters of DNA, RNA, and proteins in the nucleus of a cell

Genes

DNA segments that serve as the key functional units in hereditary transmission.

basic units of inheritance in chromosomes

Alleles

different versions of a gene

if 2 versions of alleles are found together

- Dominant: allele that is observable (represented by a capital letter)

- Recessive: allele whose effects are hidden (represented by lowercase letter)

Homozygous

having two identical alleles for a particular gene

pair of chromosomes having IDENTICAL alleles

-EXAMPLE: hair color in chromosome pair 5: both parents having "blonde" gene

Heterozygous

having two different alleles for a particular gene

pair of chromosomes having DIFFERENT alleles

-EXAMPLE: hair color in chromosome pair 5: one parent has a "brunette" gene while the other has a "blonde" gene

Deoxyribonucleic acid (DNA)

genetic material; double helix model made of nucleotides

has information of cell in nucleus

made of building blocks called nucleotides

Mutation

alteration of genetic material (DNA)

if nucleotide is not the nucleotide that it is supposed to be → there will be a mutation on that DNA

DNA → RNA → Proteins

the way we pass information

when we talk about information, we talk about protein information

Translation

the process in which RNA leaves nucleus of cell and travels towards cytoplasm, meets with ribosomes and rough ER to make proteins

Genotype

genetic constitution of an individual organism

Phenotype

characteristics

observable characteristics of an individual resulting from interaction of its genotype with the environment

Single- gene disorder

Autosomal dominant inheritance

Autosomal recessive inheritance

Autosomal Dominant Inheritance

if ONE parent is affected → 50% chance of affected child

if BOTH parents are affected → 75% chance of affected child

male/female off-spring affected equally

Autosomal Recessive Inheritance

BOTH parents HAVE it

- all children will be affected

ONE parent HAS it, other IS carrier

- 50% chance of carrier child

ONE parent HAS it, other parent IS NOT carrier

- child not affected

- child WILL be carrier

BOTH parents DON'T have it, but BOTH parents ARE carriers

- 25% chance of affected child

males/female off-spring both affected equally

carriers do not show signs or symptoms

-EXAMPLE: Cystic Fibrosis → thick mucous block in respiratory, GI, & reproductive system

-EXAMPLE: Phenylketonuria →

defect in amino acid metabolism; accumulation of phenylalanine; lack of tyrosine

-EXAMPLE: Tay-Sachs Disease

→ accumulation of glycolipids in brain neurons & retina (due to failure of lysosomes (enzyme) function

Sex-linked inheritence

caused by genes located on sex chromosome

- Female: XX

- Male: XY

Most X-linked disorders → recessive

- usually affects MALES

affected males CANNOT transmit affected gene to sons

affected males CAN transmit affected genes to daughters

SONS of FEMALE carriers

- 50% chance of being affected

-EXAMPLE: Color-blindness being predominant in men

Chromosomal Disorders

two causes

1. Alteration in structure of one or more chromosomes with rearrangement/deletion of chromosome part

- radiation/chemical exposure

- viral infection

2. Abnormal # of chromosomes

-EXAMPLE: Down Syndrome (Trisomy 21) → extra chromosome

( 47 chromosomes)

-EXAMPLE: Turner Syndrome → missing sex chromosome

(45 chromosomes)