22.10: Cerego- The Respiratory System - Biology

22.10: Cerego- The Respiratory System - Biology

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It is tempting to view different topics as completely separate, but in fact the ideas we cover in this course are often connected to one another. Using this practice set can help you do well both in this module and as you move through the course.

Click here to view the practice set for The Respiratory System. You’ll need to create a free log-in to practice these items, if you haven’t already.

What Is the Structure and Function of the Respiratory Membrane?

The respiratory membrane, also called the respiratory surface, is made of the alveolar epithelial cell and the pulmonary capillary endothelial cell, and this structure helps exchange the gases of carbon dioxide and oxygen. The respiratory membrane plays a key role in exchanging gases within the lungs. This membrane also helps bring oxygen into blood and remove carbon dioxide.

The respiratory membrane contains a large surface area that is covered by thousands of smaller cell structures called alveoli. The large and permeable surface of the respiratory membrane makes it well suited for facilitating the exchange of gases that are produced and used for vital functions, such as respiration and metabolism. Gas exchange is a critical part of allowing bodies to function properly. Humans consume large quantities of oxygen, which is used by cells to produce energy and carry out basic tasks. The use of oxygen ultimately produces a waste product in the form of carbon dioxide, which must be expelled to avoid building up in the body. The respiratory membrane allows for the seamless transition of oxygen and carbon dioxide particles across its surface, as it is smooth and thin, and requires the gases to travel very short distances. Having a short travel time allows for a faster, more energy-efficient exchange of gases.

Organs and Structures of the Respiratory System

  • List the structures that make up the respiratory system
  • Describe how the respiratory system processes oxygen and CO2
  • Compare and contrast the functions of upper respiratory tract with the lower respiratory tract

The major organs of the respiratory system function primarily to provide oxygen to body tissues for cellular respiration, remove the waste product carbon dioxide, and help to maintain acid-base balance. Portions of the respiratory system are also used for non-vital functions, such as sensing odors, speech production, and for straining, such as during childbirth or coughing (Figure 22.2).

Figure 22.2 Major Respiratory Structures The major respiratory structures span the nasal cavity to the diaphragm.

Functionally, the respiratory system can be divided into a conducting zone and a respiratory zone. The conducting zone of the respiratory system includes the organs and structures not directly involved in gas exchange. The gas exchange occurs in the respiratory zone.

Conducting Zone

The major functions of the conducting zone are to provide a route for incoming and outgoing air, remove debris and pathogens from the incoming air, and warm and humidify the incoming air. Several structures within the conducting zone perform other functions as well. The epithelium of the nasal passages, for example, is essential to sensing odors, and the bronchial epithelium that lines the lungs can metabolize some airborne carcinogens.

The Nose and its Adjacent Structures

The major entrance and exit for the respiratory system is through the nose. When discussing the nose, it is helpful to divide it into two major sections: the external nose, and the nasal cavity or internal nose.

The external nose consists of the surface and skeletal structures that result in the outward appearance of the nose and contribute to its numerous functions (Figure 22.3). The root is the region of the nose located between the eyebrows. The bridge is the part of the nose that connects the root to the rest of the nose. The dorsum nasi is the length of the nose. The apex is the tip of the nose. On either side of the apex, the nostrils are formed by the alae (singular = ala). An ala is a cartilaginous structure that forms the lateral side of each naris (plural = nares), or nostril opening. The philtrum is the concave surface that connects the apex of the nose to the upper lip.

Figure 22.3 Nose This illustration shows features of the external nose (top) and skeletal features of the nose (bottom).

Underneath the thin skin of the nose are its skeletal features (see Figure 22.3, lower illustration). While the root and bridge of the nose consist of bone, the protruding portion of the nose is composed of cartilage. As a result, when looking at a skull, the nose is missing. The nasal bone is one of a pair of bones that lies under the root and bridge of the nose. The nasal bone articulates superiorly with the frontal bone and laterally with the maxillary bones. Septal cartilage is flexible hyaline cartilage connected to the nasal bone, forming the dorsum nasi. The alar cartilage consists of the apex of the nose it surrounds the naris.

The nares open into the nasal cavity, which is separated into left and right sections by the nasal septum (Figure 22.4). The nasal septum is formed anteriorly by a portion of the septal cartilage (the flexible portion you can touch with your fingers) and posteriorly by the perpendicular plate of the ethmoid bone (a cranial bone located just posterior to the nasal bones) and the thin vomer bones (whose name refers to its plough shape). Each lateral wall of the nasal cavity has three bony projections, called the superior, middle, and inferior nasal conchae. The inferior conchae are separate bones, whereas the superior and middle conchae are portions of the ethmoid bone. Conchae serve to increase the surface area of the nasal cavity and to disrupt the flow of air as it enters the nose, causing air to bounce along the epithelium, where it is cleaned and warmed. The conchae and meatuses also conserve water and prevent dehydration of the nasal epithelium by trapping water during exhalation. The floor of the nasal cavity is composed of the palate. The hard palate at the anterior region of the nasal cavity is composed of bone. The soft palate at the posterior portion of the nasal cavity consists of muscle tissue. Air exits the nasal cavities via the internal nares and moves into the pharynx.

Several bones that help form the walls of the nasal cavity have air-containing spaces called the paranasal sinuses, which serve to warm and humidify incoming air. Sinuses are lined with a mucosa. Each paranasal sinus is named for its associated bone: frontal sinus, maxillary sinus, sphenoidal sinus, and ethmoidal sinus. The sinuses produce mucus and lighten the weight of the skull.

The nares and anterior portion of the nasal cavities are lined with mucous membranes, containing sebaceous glands and hair follicles that serve to prevent the passage of large debris, such as dirt, through the nasal cavity. An olfactory epithelium used to detect odors is found deeper in the nasal cavity.

The conchae, meatuses, and paranasal sinuses are lined by respiratory epithelium composed of pseudostratified ciliated columnar epithelium (Figure 22.5). The epithelium contains goblet cells, one of the specialized, columnar epithelial cells that produce mucus to trap debris. The cilia of the respiratory epithelium help remove the mucus and debris from the nasal cavity with a constant beating motion, sweeping materials towards the throat to be swallowed. Interestingly, cold air slows the movement of the cilia, resulting in accumulation of mucus that may in turn lead to a runny nose during cold weather. This moist epithelium functions to warm and humidify incoming air. Capillaries located just beneath the nasal epithelium warm the air by convection. Serous and mucus-producing cells also secrete the lysozyme enzyme and proteins called defensins, which have antibacterial properties. Immune cells that patrol the connective tissue deep to the respiratory epithelium provide additional protection.

Figure 22.5 Pseudostratified Ciliated Columnar Epithelium Respiratory epithelium is pseudostratified ciliated columnar epithelium. Seromucous glands provide lubricating mucus. LM × 680. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)


View the University of Michigan WebScope to explore the tissue sample in greater detail.


The pharynx is a tube formed by skeletal muscle and lined by mucous membrane that is continuous with that of the nasal cavities (see Figure 22.4). The pharynx is divided into three major regions: the nasopharynx, the oropharynx, and the laryngopharynx (Figure 22.6).

Figure 22.6 Divisions of the Pharynx The pharynx is divided into three regions: the nasopharynx, the oropharynx, and the laryngopharynx.

The nasopharynx is flanked by the conchae of the nasal cavity, and it serves only as an airway. At the top of the nasopharynx are the pharyngeal tonsils. A pharyngeal tonsil, also called an adenoid, is an aggregate of lymphoid reticular tissue similar to a lymph node that lies at the superior portion of the nasopharynx. The function of the pharyngeal tonsil is not well understood, but it contains a rich supply of lymphocytes and is covered with ciliated epithelium that traps and destroys invading pathogens that enter during inhalation. The pharyngeal tonsils are large in children, but interestingly, tend to regress with age and may even disappear. The uvula is a small bulbous, teardrop-shaped structure located at the apex of the soft palate. Both the uvula and soft palate move like a pendulum during swallowing, swinging upward to close off the nasopharynx to prevent ingested materials from entering the nasal cavity. In addition, auditory (Eustachian) tubes that connect to each middle ear cavity open into the nasopharynx. This connection is why colds often lead to ear infections.

The oropharynx is a passageway for both air and food. The oropharynx is bordered superiorly by the nasopharynx and anteriorly by the oral cavity. The fauces is the opening at the connection between the oral cavity and the oropharynx. As the nasopharynx becomes the oropharynx, the epithelium changes from pseudostratified ciliated columnar epithelium to stratified squamous epithelium. The oropharynx contains two distinct sets of tonsils, the palatine and lingual tonsils. A palatine tonsil is one of a pair of structures located laterally in the oropharynx in the area of the fauces. The lingual tonsil is located at the base of the tongue. Similar to the pharyngeal tonsil, the palatine and lingual tonsils are composed of lymphoid tissue, and trap and destroy pathogens entering the body through the oral or nasal cavities.

The laryngopharynx is inferior to the oropharynx and posterior to the larynx. It continues the route for ingested material and air until its inferior end, where the digestive and respiratory systems diverge. The stratified squamous epithelium of the oropharynx is continuous with the laryngopharynx. Anteriorly, the laryngopharynx opens into the larynx, whereas posteriorly, it enters the esophagus.


The larynx is a cartilaginous structure inferior to the laryngopharynx that connects the pharynx to the trachea and helps regulate the volume of air that enters and leaves the lungs (Figure 22.7). The structure of the larynx is formed by several pieces of cartilage. Three large cartilage pieces&mdashthe thyroid cartilage (anterior), epiglottis (superior), and cricoid cartilage (inferior)&mdashform the major structure of the larynx. The thyroid cartilage is the largest piece of cartilage that makes up the larynx. The thyroid cartilage consists of the laryngeal prominence, or &ldquoAdam&rsquos apple,&rdquo which tends to be more prominent in males. The thick cricoid cartilage forms a ring, with a wide posterior region and a thinner anterior region. Three smaller, paired cartilages&mdashthe arytenoids, corniculates, and cuneiforms&mdashattach to the epiglottis and the vocal cords and muscle that help move the vocal cords to produce speech.

Figure 22.7 Larynx The larynx extends from the laryngopharynx and the hyoid bone to the trachea.

The epiglottis, attached to the thyroid cartilage, is a very flexible piece of elastic cartilage that covers the opening of the trachea (see Figure 22.4). When in the &ldquoclosed&rdquo position, the unattached end of the epiglottis rests on the glottis. The glottis is composed of the vestibular folds, the true vocal cords, and the space between these folds (Figure 22.8). A vestibular fold, or false vocal cord, is one of a pair of folded sections of mucous membrane. A true vocal cord is one of the white, membranous folds attached by muscle to the thyroid and arytenoid cartilages of the larynx on their outer edges. The inner edges of the true vocal cords are free, allowing oscillation to produce sound. The size of the membranous folds of the true vocal cords differs between individuals, producing voices with different pitch ranges. Folds in males tend to be larger than those in females, which create a deeper voice. The act of swallowing causes the pharynx and larynx to lift upward, allowing the pharynx to expand and the epiglottis of the larynx to swing downward, closing the opening to the trachea. These movements produce a larger area for food to pass through, while preventing food and beverages from entering the trachea.

Figure 22.8 Vocal Cords The true vocal cords and vestibular folds of the larynx are viewed inferiorly from the laryngopharynx.

Continuous with the laryngopharynx, the superior portion of the larynx is lined with stratified squamous epithelium, transitioning into pseudostratified ciliated columnar epithelium that contains goblet cells. Similar to the nasal cavity and nasopharynx, this specialized epithelium produces mucus to trap debris and pathogens as they enter the trachea. The cilia beat the mucus upward towards the laryngopharynx, where it can be swallowed down the esophagus.


The trachea (windpipe) extends from the larynx toward the lungs (Figure 22.9a). The trachea is formed by 16 to 20 stacked, C-shaped pieces of hyaline cartilage that are connected by dense connective tissue. The trachealis muscle and elastic connective tissue together form the fibroelastic membrane, a flexible membrane that closes the posterior surface of the trachea, connecting the C-shaped cartilages. The fibroelastic membrane allows the trachea to stretch and expand slightly during inhalation and exhalation, whereas the rings of cartilage provide structural support and prevent the trachea from collapsing. In addition, the trachealis muscle can be contracted to force air through the trachea during exhalation. The trachea is lined with pseudostratified ciliated columnar epithelium, which is continuous with the larynx. The esophagus borders the trachea posteriorly.

Figure 22.9 Trachea (a) The tracheal tube is formed by stacked, C-shaped pieces of hyaline cartilage. (b) The layer visible in this cross-section of tracheal wall tissue between the hyaline cartilage and the lumen of the trachea is the mucosa, which is composed of pseudostratified ciliated columnar epithelium that contains goblet cells. LM × 1220. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)

Bronchial Tree

The trachea branches into the right and left primary bronchi at the carina. These bronchi are also lined by pseudostratified ciliated columnar epithelium containing mucus-producing goblet cells (Figure 22.9b). The carina is a raised structure that contains specialized nervous tissue that induces violent coughing if a foreign body, such as food, is present. Rings of cartilage, similar to those of the trachea, support the structure of the bronchi and prevent their collapse. The primary bronchi enter the lungs at the hilum, a concave region where blood vessels, lymphatic vessels, and nerves also enter the lungs. The bronchi continue to branch into bronchial a tree. A bronchial tree (or respiratory tree) is the collective term used for these multiple-branched bronchi. The main function of the bronchi, like other conducting zone structures, is to provide a passageway for air to move into and out of each lung. In addition, the mucous membrane traps debris and pathogens.

A bronchiole branches from the tertiary bronchi. Bronchioles, which are about 1 mm in diameter, further branch until they become the tiny terminal bronchioles, which lead to the structures of gas exchange. There are more than 1000 terminal bronchioles in each lung. The muscular walls of the bronchioles do not contain cartilage like those of the bronchi. This muscular wall can change the size of the tubing to increase or decrease airflow through the tube.

Respiratory Zone

In contrast to the conducting zone, the respiratory zone includes structures that are directly involved in gas exchange. The respiratory zone begins where the terminal bronchioles join a respiratory bronchiole, the smallest type of bronchiole (Figure 22.10), which then leads to an alveolar duct, opening into a cluster of alveoli.

Figure 22.10 Respiratory Zone Bronchioles lead to alveolar sacs in the respiratory zone, where gas exchange occurs.


An alveolar duct is a tube composed of smooth muscle and connective tissue, which opens into a cluster of alveoli. An alveolus is one of the many small, grape-like sacs that are attached to the alveolar ducts.

An alveolar sac is a cluster of many individual alveoli that are responsible for gas exchange. An alveolus is approximately 200 &mum in diameter with elastic walls that allow the alveolus to stretch during air intake, which greatly increases the surface area available for gas exchange. Alveoli are connected to their neighbors by alveolar pores, which help maintain equal air pressure throughout the alveoli and lung (Figure 22.11).

Figure 22.11 Structures of the Respiratory Zone (a) The alveolus is responsible for gas exchange. (b) A micrograph shows the alveolar structures within lung tissue. LM × 178. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)

The alveolar wall consists of three major cell types: type I alveolar cells, type II alveolar cells, and alveolar macrophages. A type I alveolar cell is a squamous epithelial cell of the alveoli, which constitute up to 97 percent of the alveolar surface area. These cells are about 25 nm thick and are highly permeable to gases. A type II alveolar cell is interspersed among the type I cells and secretes pulmonary surfactant, a substance composed of phospholipids and proteins that reduces the surface tension of the alveoli. Roaming around the alveolar wall is the alveolar macrophage, a phagocytic cell of the immune system that removes debris and pathogens that have reached the alveoli.

The simple squamous epithelium formed by type I alveolar cells is attached to a thin, elastic basement membrane. This epithelium is extremely thin and borders the endothelial membrane of capillaries. Taken together, the alveoli and capillary membranes form a respiratory membrane that is approximately 0.5 &mum (micrometers) thick. The respiratory membrane allows gases to cross by simple diffusion, allowing oxygen to be picked up by the blood for transport and CO2 to be released into the air of the alveoli.


Respiratory System: Asthma

Asthma is common condition that affects the lungs in both adults and children. Approximately 8.2 percent of adults (18.7 million) and 9.4 percent of children (7 million) in the United States suffer from asthma. In addition, asthma is the most frequent cause of hospitalization in children.

Asthma is a chronic disease characterized by inflammation and edema of the airway, and bronchospasms (that is, constriction of the bronchioles), which can inhibit air from entering the lungs. In addition, excessive mucus secretion can occur, which further contributes to airway occlusion (Figure 22.12). Cells of the immune system, such as eosinophils and mononuclear cells, may also be involved in infiltrating the walls of the bronchi and bronchioles.

Bronchospasms occur periodically and lead to an &ldquoasthma attack.&rdquo An attack may be triggered by environmental factors such as dust, pollen, pet hair, or dander, changes in the weather, mold, tobacco smoke, and respiratory infections, or by exercise and stress.

Figure 22.12 Normal and Bronchial Asthma Tissues (a) Normal lung tissue does not have the characteristics of lung tissue during (b) an asthma attack, which include thickened mucosa, increased mucus-producing goblet cells, and eosinophil infiltrates.

Symptoms of an asthma attack involve coughing, shortness of breath, wheezing, and tightness of the chest. Symptoms of a severe asthma attack that requires immediate medical attention would include difficulty breathing that results in blue (cyanotic) lips or face, confusion, drowsiness, a rapid pulse, sweating, and severe anxiety. The severity of the condition, frequency of attacks, and identified triggers influence the type of medication that an individual may require. Longer-term treatments are used for those with more severe asthma. Short-term, fast-acting drugs that are used to treat an asthma attack are typically administered via an inhaler. For young children or individuals who have difficulty using an inhaler, asthma medications can be administered via a nebulizer.

In many cases, the underlying cause of the condition is unknown. However, recent research has demonstrated that certain viruses, such as human rhinovirus C (HRVC), and the bacteria Mycoplasma pneumoniae and Chlamydia pneumoniae that are contracted in infancy or early childhood, may contribute to the development of many cases of asthma.


Visit this site to learn more about what happens during an asthma attack. What are the three changes that occur inside the airways during an asthma attack?

The body of water that lies south of Cuba and east of Central America is the A Gulf of California B. Gulf of Mexico C. Rio Grande D. Caribbean Sea PLEASE HURRY IM TIMED

The Gulf of Mexico is above the Caribbean sea so the answer must be the Caribbean sea.


All of these terms are related to Latin America. Latin America is a group of countries in the Western Hemisphere that speak a Romance language (for the most part, Spanish and Portuguese). This does not include the French areas of Canada (such as Quebec) or the Spanish-speaking areas of the United States (such as Puerto Rico). Latin America represents roughly 13% of the land surface of the Earth.

1. Brazil. This country, the largest in South America, is a federative republic and is the only American country to use Portuguese as its official language

2. Venezuela. This country was once a Spanish colony and is one of the major exporters of oil in the Western Hemisphere.

3. Andes. This mountain range is found in South America and was home to the Incan Empire.

4. Amazon. This is the largest river (by volume of water) in the world and it runs through the northern regions of South America.

5. Caribbean. This body of water to the north of South America contains the countries of Cuba and Jamaica.

6. Pacific Ocean. This body of water stretches from North and South America westward to Australia and the eastern coast of Asia.

7. Panama. This country is located in an isthmus between Central and South America.

8. Mexico. This country was once home to the Maya and Aztec civilizations, came under Spanish control in the 1500s, and since 1917 has been a representative, democratic republic with a presidential system.

Human respiratory system

The respiratory system is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary history.

A. Parts of the human respiratory system

Air enters the respiratory system through the nose and mouth and passes down the throat (pharynx) and through the voice box, or larynx. The entrance to the larynx is covered by a small flap of tissue (epiglottis) that automatically closes during swallowing, thus preventing food or drink from entering the airways

cup cell so cool choir so do so DL DL so do so so rip to to to to do

i think the answer is D. same answer with me:)

The respiratory system includes the nose, mouth, throat, voice box, windpipe, and lungs.Air enters the respiratory system through the nose or the mouth. If it goes in the nostrils (also called nares), the air is warmed and humidified. Tiny hairs called cilia (SIL-ee-uh) protect the nasal passageways and other parts of the respiratory tract, filtering out dust and other particles that enter the nose through the breathed air.The two openings of the airway (the nasal cavity and the mouth) meet at the pharynx (FAR-inks), or throat, at the back of the nose and mouth. The pharynx is part of the digestive system as well as the respiratory system because it carries both food and air.At the bottom of the pharynx, this pathway divides in two, one for food — the esophagus (ih-SAH-fuh-gus), which leads to the stomach — and the other for air. The epiglottis (eh-pih-GLAH-tus), a small flap of tissue, covers the air-only passage when we swallow, keeping food and liquid from going into the lungs.The larynx, or voice box, is the top part of the air-only pipe. This short tube contains a pair of vocal cords, which vibrate to make sounds.The trachea, or windpipe, is the continuation of the airway below the larynx. The walls of the trachea (TRAY-kee-uh) are strengthened by stiff rings of cartilage to keep it open. The trachea is also lined with cilia, which sweep fluids and foreign particles out of the airway so that they stay out of the lungs.At its bottom end, the trachea divides into left and right air tubes called bronchi (BRAHN-kye), which connect to the lungs. Within the lungs, the bronchi branch into smaller bronchi and even smaller tubes called bronchioles (BRAHN-kee-olz). Bronchioles end in tiny air sacs called alveoli, where the exchange of oxygen and carbon dioxide actually takes place. Each person has hundreds of millions of alveoli in their lungs. This network of alveoli, bronchioles, and bronchi is known as the bronchial tree.The lungs also contain elastic tissues that allow them to inflate and deflate without losing shape and are covered by a thin lining called the pleura (PLUR-uh).The chest cavity, or thorax (THOR-aks), is the airtight box that houses the bronchial tree, lungs, heart, and other structures. The top and sides of the thorax are formed by the ribs and attached muscles, and the bottom is formed by a large muscle called the diaphragm (DYE-uh-fram). The chest walls form a protective cage around the lungs and other contents of the chest cavity.

the number of dots will increase but as the dots go farther from the center, the number of dots will decrease.

When a cell divides it copies each one of its chromosomes prior to dividing. the process of mitosis results in one full set of chromosomes at the pole of each cell. the cell then divides into two cells. each of these two new cells has one full set of chromosomes.

Structures of the Conducting Zone

External nares (the nostrils)

· hair in the vestibule removes airborne particles

· primary route for entering air

· bony portion = perpendicular plate of the ethmoid bone and vomer bone union

· works with cartilage to form full septum

Nasal conchae (aka, turbinates)

· cause the air to swirl in the nasal cavity and come in contact with mucous membrane covering (which catches debris/dust)

· heat and humidify the air for respiration – allows diffusion of gases in lung


flips up during swallowing to prevent fluids from entering the nasopharynx (soft palate also raises to prevent food from entering)

The Pharynx is divided into 3 anatomical regions:

1. Nasopharynx

· Passageway for airflow from nasal cavity

· Has pseudostratified ciliated columnar epithelieum, pharyngeal tonsils, and eustachian tubes

· common passageway for food, water, and air

· stratified squamous epithelium (in common with oral cavity)

· Contains palatine and lingual tonsils

3. Laryngopharynx

· stratified squamous epithelium


During swallowing, the hyoid bone lifts causing the epiglottis to lower and protect the glottis, which consists of the opening in the larynx and the vocal cords.


· false vocal cords (Vestibular ligaments and folds)

o During coughing or sneezing, close over the glottis

o Superior to the true vocal cords

· true vocal cords (Vocal ligaments and folds)

o Responsible for sound production

o Only produces sound when air is exhaled over them

o Sounds change when cords are stretched or relaxed

Larynx (Voice Box)

1 thyroid cartilage (Adam’s apple)

1 cricoid cartilage (connects larynx to trachea)

  • Q:- Write true or false. If false change the statement so that it is true.
    (a) Actin is present in thin filament
    (b) H-zone of striated muscle fibre represents both thick and thin filaments.
    (c) Human skeleton has 206 bones.
    (d) There are 11 pairs of ribs in man.
    (e) Sternum is present on the ventral side of the body.
  • Q:- Explain the following processes:
    (a) Polarisation of the membrane of a nerve fibre
    (b) Depolarisation of the membrane of a nerve fibre
    (c) Conduction of a nerve impulse along a nerve fibre
    (d) Transmission of a nerve impulse across a chemical synapse
  • Q:- Explain the process of secondary growth in stems of woody angiosperm with help of schematic diagrams. What is the significance?
  • Q:- Describe the events taking place during interphase.
  • Q:- Diagrammatically indicate the location of the various endocrine glands in our body.
  • Q:- What are the modifications that are observed in birds that help them fly?
  • Q:- Describe the important properties of enzymes.
  • Q:- Find examples where the four daughter cells from meiosis are equal in size and where they are found unequal in size.
  • Q:-

Describe the structure of the following with the help of labelled diagrams.
(i) Nucleus
(ii) Centrosome

What are the limitations of the respiratory system?

The respiratory system contributes in three major ways to limitations in arterial O2 content and/or blood flow during high-intensity exercise, namely: 1) exerciseinduced arterial hypoxemia (EIAH) which occurs to a highly variable extent among highly trained male and female runners 2) intrathoracic pressure effects on

Having gills, or the ability of gills.

Our lungs can't filter out water and use the oxygen in the water, sadly.

And, we can't hold our breath for that long, compared to other mammals (the only way that we can hold our breath for a long time is if we breathe in pure oxygen).

littering streams is the answer

preservation because he preserves part of the land and preserves means save


Due to the uncountable mechanisms of action addressed in this and other reviews, it has been reinforced that curcumin could serve as an adjuvant drug in COVID-19 treatment (Babaei et al., 2020 Manoharan et al., 2020 Roy et al., 2020 Soni et al., 2020 Zahedipour et al., 2020 Saeedi-Boroujeni et al., 2021 Thimmulappa et al., 2021). The multiplicity of pathophysiological responses induced by SARS-CoV-2 highlights the need for a combination of different drugs as a treatment strategy (i.e., there is no single "magic pill" for the cure of COVID-19). Curcumin is a well-tolerated natural compound in humans, even at high concentrations (Dhillon et al., 2008 Kanai et al., 2011 Gupta et al., 2013). Thus, its combination with drugs that are already approved for use appears logical. Curcumin is a well-tolerated natural compound in humans, even at high concentrations (Dhillon et al., 2008 Kanai et al., 2011 Gupta et al., 2013). Thus, its combination with drugs that are already approved for use appears logical. The first results from the studies regarding the effect of curcumin in patients with COVID-19 are promising. However, several questions need to be answered: 1) Does curcumin prevent SARS-CoV-2 infection of the host cells? 2) Does curcumin treatment attenuate respiratory and cardiovascular system commitment? 3) Is the curcumin able to reestablish hemostatic homeostasis?

Despite the absence of specific studies addressing the mechanism of action of curcumin in the treatment of COVID-19, currently, the world is experiencing an uncommon situation, which has led researchers and physicians to evaluate the available knowledge to the other diseases, in an attempt to design more promising pathways against SARS-CoV-2. In conclusion, this review strategically contributes to the relentless search for therapies that can act on combat of COVID-19, in addition to providing targets for future studies using the curcumin as an adjuvant treatment to COVID-19.

22.10: Cerego- The Respiratory System - Biology


The movement from water to land was a critical evolutionary transformation for both vertebrates and arthropods (insects, spiders, millipedes, crustaceans, etc.). Different groups of arthropods used different methods to enable breathing air, a critical requirement for life on land, a change that occurred separately in at least 7 groups. The goal of this project is to investigate how an air-breathing respiratory system evolved separately in multiple arthropod groups. Did evolution of aerial respiration involve alteration to the same anatomical structures and genes in each group, or does each arthropod group use a different solution to the problem of breathing air? To resolve this question, the embryonic formation of respiratory organs in eight arthropod species will be investigated. Genes and proteins will be tested to determine whether the same genes are used in the respiratory system of all arthropods. Genome sequencing will further test and identify genes that create unique respiratory structures (e.g., the book lung of spiders). The outcomes of this research will be integrated into a new laboratory-based course on invertebrate zoology, to be taught annually through the Department of Zoology, using live specimens. A museum exhibit will be developed on the movement of arthropods onto land, and using evidence from fossils, genes, and developmental biology. One postdoctoral fellow, one graduate student, and ten summer undergraduates will be trained during the work, emphasizing recruitment of women and underrepresented groups in science.

Investigating the parallel evolution of aerial respiration in Arthropoda has previously been limited to studies of functional morphology or expression data from a few taxa. Some developmental data suggest that mandibulate and chelicerate respiratory systems are directly homologous, whereas a separate set of data suggests that respiratory organs of arachnids arose independently from modified walking legs. Respiratory systems of Myriapoda have not been studied in a developmental genetic context at all. To resolve the origins of internalized respiratory systems of arthropods, the proposed work will examine positional, genetic, and serial homology of respiratory organs in eight emerging model arthropod systems. To establish the serial homology of arachnid respiratory organs, Hox misexpression experiments will be conducted to derepress appendages in posterior segments. To establish degree of conservation of the gene regulatory network (GRN) underlying tubulogenesis across Arthropoda, gene expression assays will be performed for candidate genes known to be required for establishment of the Drosophila melanogaster tracheal tubule system. To assess functional correspondence, knockdown experiments will be conducted in two chelicerate and three mandibulate exemplars for five critical genes in the Drosphila GRN. To investigate the patterning of the arachnid book lung, comparative transcriptomic data will be generated from book lung primordia of spiders and scorpions, toward identifying a set of novel candidate genes putatively involved in book lung morphogenesis for further functional screening. This work will directly address the two competing scenarios of arthropod terrestrialization that persist in the literature, using independent tests of positional, serial, and genetic homology.


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Watch the video: Respiratory System: OxygenTransport (February 2023).