UWC Quiz 3

Components of the respiratory system.

nares, nasal cavity, pharynx, glottis, larynx, trachea, two bronchi, bronchioles, alveoli

nares component/function

The openings in the nose.

nasal cavity component/function

Lined with fine hairs, filters particulates, slows and warms air

pharynx components/function

back of mouth, soft palate, respiratory and digestive system

glottis components/function

opening to larynx, covered by epiglottis

trachea components/function

ringed with cartilage. Without cartilage the negative pressure caused by inhalation would collapse and close, this would cause inhalation to fail. The rings aren’t complete because they allow food to pass along esophagus without obstruction.

bronchi components/function

1 to each lung, also ringed with cartilage, divide to form. Without cartilage the negative pressure caused by inhalation would collapse and close, this would cause inhalation to fail. The rings aren’t complete because they allow food to pass along esophagus without obstruction.

alveoli components/function

site of gas exchange, functional unit of lung. Moist thin-walled pockets which are site of gas exchange.

Pathway of air in and out

nares, it then goes through the nasal cavity, it then reaches through the pharynx, and then the glottis, it then goes through the larynx, the air enters the trachea, then it reaches the two bronchi, then the air enters through the bronchioles, then it enters the alveoli. 

How ventilation works (breathing)

changing thoracic cavity volume, which alters lung pressure relative to the atmosphere, driven primarily by the diaphragm and intercostal muscles contracting for inhalation and relaxing for exhalation. 
Negative pressure model, thoracic cavity, sealed chamber, volume of gas is constant, decrease pressure, decrease cavity size, increase pressure.

Inhalation

intercostal muscles (ribs): contract ribs come up and out

-Diaphragm: contracts, pulls down

-Volume of thoracic cavity: increases, negative pressure (reduced)

-Alveoli inflate because they’re elastic, air rushes in

Exhalation

Relax: intercostal muscles (ribs): ribs go down and in

-Diaphragm: springs back up

-Volume of thoracic cavity: decreases, pressure increases

-Alveoli deflate because they’re elastic, air forced out

MRNA strand is

5’-3’

CDNA strand is

3’-5’

Differential expression

The expression of genes only at certain times during development, under specific conditions, or in particular tissues

Mutations (can be caused by errors in DNA replication) and carcinogens can cause this.

How differential expression is controlled

regulating which genes are turned on or off in a cell, allowing identical genomes to produce diverse cell types. This is achieved through transcriptional regulation (transcription factors binding to enhancers/silencers), epigenetic changes (DNA methylation/histone modification), and post-transcriptional RNA-binding factors.

Carcinogen

Chemicals demonstrated to cause cancer

Proto-oncogene

promote speed through the cycle. normal genes that regulate cell growth, division, and survival. Increase expression of this promotes cancer

Tumor suppressor

essential protective genes that regulate cell growth, repair DNA damage, and trigger apoptosis (cell death) to prevent cancer. Decreased expression of this increases cancer.

Metastasis

Spreading of cancer cells to other areas of the body. It usually travels through the blood (circulates in blood vessels) or lymph (circulated in lymph vessels)

Why does metastases tend to travel to the lungs

because the lungs act as the body's first major capillary filter for blood returning from the rest of the body

Different kinds of lung cancer

Mesothelioma: cancer that develops from the lining of the lungs. People who are exposed to/work with asbestos are at a higher risk

Small cell lung cancer: AKA Oat cell cancer. Begins in the bronchi, very aggressive, classified by its locks under the microscope

Non-small cell lung cancer: Classified by its look under microscope. more common, better prognosis. Have different subtypes that are named after the cell type that the cancer develops from. (adenocarcinoma- develops from epithelial tissue)

How lung cancer is diagnosed

Microarrays. through a combination of imaging tests (CT or PET scans) to locate suspicious areas, followed by a biopsy (tissue sample) to confirm the presence and type of cancer. Specialized procedures like bronchoscopy or needle biopsies are used to collect samples for laboratory testing. 

Wedge resection

removal of part of the lungs where the tumor resides (surgery)

Cisplatin

It binds to DNA which prevents DNA replication. Chemotherapy medication.

Paclitaxel

Halts cells in mPhase of the cell cycle; it prevents mitosis. intravenous chemotherapy drug.

Diffusion

It is essential for transporting oxygen, carbon dioxide, and nutrients across cell membranes. It continues until equilibrium is reached. 

Internal Respiration

Exchange of oxygen and carbon dioxide at the cells and blood vessels. O2 concentration high in blood stream, low in cells, passes from blood to cells, diffusion

External Respiration

Exchange of oxygen and carbon dioxide at the alveoli in the lungs and blood vessels. CO2 high in cells and low in blood. Diffusion, passes from cells to blood.

Microarrays

Looks at changes in gene expression between tumor cells and normal cells. Analyze differential gene expression through isolating RNA. If RNA is present, transcription of a particular gene is occurring which infers that gene expression is occurring.

What red means on a microarray (How is application used in clinic)

Highly expressed in tumor tissue.

What yellow means on a microarray (How is application used in clinic)

Highly expressed in both normal and tumor tissue.

What green means on a microarray (How is application used in clinic)

Highly expressed in normal tissue. Usually means it could be a tumor suppressor but if you have more green than red in a gene it could be involved in promoting cancer.