Biology

Function of Red Blood Cell (erythrocyte)

Carry oxygen from the lungs to the rest of the body and return carbon dioxide to the lungs for exhalation.

Function of White Blood Cell (Leukocytes)

Defend the body against infections and foreign substances.

Function of Platelets

Platelets are tiny blood cells that help your body form clots to stop bleeding

Function of Plasma

Transports nutrients, hormones, and waste products. Maintains blood pressure and pH balance.

How do red blood cells transport oxygen around the body?

Red blood cells (RBCs) use hemoglobin to carry oxygen around the body. In the lungs, hemoglobin grabs onto oxygen, forming oxyhemoglobin. As RBCs travel through arteries, they drop off oxygen where it's needed in tissues. In tissues with low oxygen, oxyhemoglobin lets go of its oxygen. The now oxygen-poor blood, carrying carbon dioxide, heads back to the lungs through veins. In the lungs, carbon dioxide is swapped for fresh oxygen, and the cycle repeats. This way, RBCs make sure your body gets the oxygen it needs for energy.

What are arteries

• Transport: Arteries carry oxygenated blood away from the heart to supply various body tissues and organs.

• Structure: Comprising an endothelial lining, smooth muscle, and connective tissue, arteries are highly elastic to accommodate the pulsating blood flow from the heart.

• Pressure: Arteries operate under high pressure, especially during the heart's contraction (systole), ensuring efficient blood distribution throughout the body.

• Distribution: Arteries branch into smaller arterioles and further into capillaries, facilitating the exchange of oxygen and nutrients with tissues

What are capillaries

• Transport: Capillaries are tiny blood vessels that connect arteries to veins, facilitating the exchange of oxygen, nutrients, and waste products with tissues.

• Structure: Capillaries consist of a single layer of endothelial cells, allowing for the efficient exchange of substances between the blood and surrounding tissues. They are the smallest and thinnest blood vessels in the body.

• Pressure: Capillaries have low pressure, allowing for the controlled and selective exchange of substances between the blood and tissues. This is essential for nutrient delivery and waste removal.

• Distribution: Capillaries form extensive networks in tissues, bringing them in close proximity to cells. Their intricate structure maximizes the surface area for exchange and ensures that every cell in the body is supplied with necessary substances.

What are veins

• Transport: Veins are blood vessels that carry deoxygenated blood back to the heart from various body tissues and organs.

• Structure: Veins have thinner walls compared to arteries and consist of three layers: an inner endothelium, a middle layer of smooth muscle, and an outer layer of connective tissue. They also have valves that prevent backward flow of blood.

• Pressure: Veins operate under lower pressure than arteries. The contraction of surrounding muscles and the presence of valves assist in propelling blood towards the heart, especially in areas where gravitational forces may impede blood flow.

• Distribution: Veins collect blood from capillaries and gradually merge into larger veins, ultimately returning deoxygenated blood to the heart for reoxygenation.

How does gas exchange occur between the capillaries and alveoli?

• Location: Gas exchange occurs in the lungs between the tiny air sacs called alveoli and the surrounding capillaries.

• Process: Oxygenated blood from the heart reaches the lungs via pulmonary arteries. In the alveoli, oxygen diffuses across the thin alveolar walls into the surrounding capillaries.

• Oxygen Binding: Hemoglobin in red blood cells binds with the oxygen in the capillaries, forming oxyhemoglobin. This oxygen-loaded blood is then carried back to the heart via pulmonary veins.

• Carbon Dioxide Release: Simultaneously, carbon dioxide, a waste product of cellular respiration, diffuses from the capillaries into the alveoli. It is then expelled from the lungs during exhalation.

• Return to the Heart: Oxygenated blood returns to the heart, where it is pumped to the rest of the body to supply tissues with oxygen. This cyclic process ensures a continuous exchange of gases necessary for cellular functions.

What are the chambers of the heart

• Atria:

  • Right Atrium: Receives deoxygenated blood from the body via the superior and inferior vena cava.

  • Left Atrium: Receives oxygenated blood from the lungs through the pulmonary veins.

• Ventricles:

  • Right Ventricle: Pumps deoxygenated blood to the lungs through the pulmonary artery for oxygenation.

  • Left Ventricle: Pumps oxygenated blood to the rest of the body through the aorta, supplying tissues with oxygen and nutrients.

Where does blood flow to and from in a mammalian heart.

In a mammalian heart, deoxygenated blood flows into the right atrium from the body through the vena cava. It then moves to the right ventricle and is pumped to the lungs through the pulmonary artery. After picking up oxygen in the lungs, the blood returns to the heart's left atrium via the pulmonary veins. From there, it moves to the left ventricle and is pumped out to the rest of the body through the mitral and aortaic valve. This process ensures that oxygen is delivered to the body's tissues and organs.

What is an open circulatory system and an example?

An open circulatory system is a type of circulatory system in which the blood or circulatory fluid is not entirely enclosed within vessels. Instead, it bathes the organs and tissues directly. The circulatory fluid, often called hemolymph, is pumped by the heart into the body cavity, where it comes into direct contact with the organs.

Example: Insects

What is a closed circulatory system and an example?

A closed circulatory system is a type of circulatory system in which blood circulates within a closed network of vessels. Blood is confined to arteries, veins, and capillaries and does not directly contact the body tissues. The heart pumps blood through this closed network, providing a more efficient and controlled means of nutrient and oxygen delivery to tissues.

Example: Mammals, including Humans:

Describe the key points about the bird circulatory system.

Birds possess a highly efficient circulatory system characterized by a four-chambered heart, featuring two atria and two ventricles. This cardiac arrangement ensures the separation of oxygenated and deoxygenated blood, contributing to efficient oxygen delivery. Birds exhibit a complete double circulatory system with distinct pulmonary and systemic circuits. Their respiratory system, including air sacs, facilitates a continuous flow of air through the lungs, enhancing oxygen exchange. Birds have a high metabolic rate, necessitating a well-developed circulatory system to meet energy demands, particularly during flight. With a rapid heart rate, developed vessels, and a keen respiratory structure, the avian circulatory system supports the physiological demands of their active lifestyles and aerial activities.

Describe the key points about amphibian circulatory system

The amphibian circulatory system is characterized by a three-chambered heart, featuring two atria and a single ventricle. This configuration allows for partial separation of oxygenated and deoxygenated blood. Amphibians undergo metamorphosis, transitioning from aquatic tadpoles to terrestrial adults, and exhibit both cutaneous and pulmonary respiration for efficient gas exchange. The heart pumps blood to both the lungs and the rest of the body, leading to some mixing of oxygenated and deoxygenated blood in the single ventricle. Well-developed vessels, including arteries, veins, and capillaries, aid in directing blood flow to the lungs and throughout the body. This circulatory adaptation allows amphibians to thrive in diverse environments, utilizing both aquatic and terrestrial habitats during different life stages.

What does a good gas exchange surface need?

1. Large Surface Area:

   • A larger surface area provides more space for gas exchange to occur, allowing for increased contact between the respiratory medium (air or water) and the respiratory surface.

2. Thin Membrane:

   • A thin and permeable membrane reduces the distance gases must diffuse, promoting a more rapid and efficient exchange of oxygen and carbon dioxide.

3. Moist Environment:

   • Gases need to dissolve in a thin layer of moisture to facilitate diffusion. A moist environment ensures that the respiratory surface stays adequately hydrated, allowing for effective gas exchange.

4. Concentration Gradient:

   • A concentration gradient, with a higher concentration of oxygen in the respiratory medium compared to the respiratory surface, facilitates the diffusion of oxygen into the organism, while a higher concentration of carbon dioxide in the organism compared to the respiratory medium promotes the removal of carbon dioxide.

Describe the key points about the fish respiratory system

The respiratory membrane of the gills is thin, facilitating the rapid diffusion of gases between the water and the fish's bloodut the fish respiratory system.

What are the 3 nitrogenous waste types and what animal example produces them?

1. Ammonia:

   • Form: Highly toxic, soluble in water.

   • Animal Example: Aquatic animals, such as fish, typically excrete ammonia directly into the water, taking advantage of its high solubility and rapid diffusion in aquatic environments.

2. Urea:

   • Form: Less toxic, soluble in water.

   • Animal Example: Mammals, including humans, produce urea as a primary nitrogenous waste. It is less toxic than ammonia and requires less water for excretion. Urea is usually excreted in urine.

3. Uric Acid:

   • Form: Insoluble in water, often forms a paste.

   • Animal Example: Birds, reptiles, and insects excrete uric acid. It is less toxic than ammonia and urea and can be excreted with minimal water loss. Birds excrete uric acid as a semisolid white paste, which helps conserve water

What is the nephron?

The nephron is the basic functional unit of the kidney, responsible for the processes of filtration, reabsorption, and secretion that collectively produce urine

What happens in the glomerulus?

In the glomerulus, blood from the renal artery is filtered under high pressure. This filtration allows water, ions, and small molecules to pass into the Bowman's capsule, forming a fluid called filtrate. The glomerulus serves as the initial site of urine formation in the kidney

What happens in the Bowmans capsule?

In Bowman's capsule, the filtrate, consisting of water, ions, and small molecules, is collected from the glomerulus. This marks the start of the kidney's process of forming urine.

What happens in the proximal tube?

In the proximal convoluted tubule (PCT), essential substances like glucose and amino acids are reabsorbed from the filtrate back into the bloodstream. Additionally, water and ions are reabsorbed, helping maintain a balance in the body. Waste products are actively secreted into the filtrate for elimination, and the PCT contributes to adjusting the body's pH.

What happens in the Loop of Henle?

In the Loop of Henle, water is reabsorbed in the descending limb, concentrating the filtrate. In the ascending limb, ions are reabsorbed, establishing an osmotic gradient. This process contributes to the kidney's ability to produce concentrated urine.

What happens in the distal tube?

In the distal convoluted tubule (DCT), ions like sodium are fine-tuned, and pH is adjusted. Hormones influence this segment, regulating the reabsorption of water and ions. The DCT makes final adjustments to the filtrate, ensuring the urine meets the body's specific needs.

What are the two types of digestion?

1. Mechanical Digestion:

   • Definition: Mechanical digestion involves the physical breakdown of food into smaller pieces without changing its chemical composition.

   • Processes: Chewing in the mouth, churning in the stomach, and segmentation in the small intestine are examples of mechanical digestion. These actions increase the surface area of food particles, facilitating subsequent chemical digestion.

2. Chemical Digestion:

   • Definition: Chemical digestion involves the enzymatic breakdown of large, complex molecules into simpler compounds that can be absorbed by the body.

   • Processes: Enzymes secreted by various digestive organs, such as salivary amylase in the mouth, gastric juices in the stomach, and pancreatic enzymes in the small intestine, participate in chemical digestion. These enzymes break down carbohydrates, proteins, and fats into their respective building blocks—simple sugars, amino acids, and fatty acids.

What are the four main roles of the digestive system?

1. Ingestion:

   • Definition: Ingestion is the process of taking food into the body through the mouth.

   • Function: It marks the beginning of the digestive process, allowing the body to obtain the necessary nutrients for energy and growth.

2. Digestion:

   • Definition: Digestion involves the breakdown of complex food molecules into simpler, absorbable forms.

   • Function: Mechanical and chemical digestion occur in various parts of the digestive tract, preparing nutrients for absorption into the bloodstream.

3. Absorption:

   • Definition: Absorption is the process by which nutrients, as well as water and electrolytes, are taken up into the bloodstream from the digestive tract.

   • Function: After digestion, nutrients are absorbed across the walls of the small intestine and transported to cells throughout the body for energy and other physiological functions.

4. Elimination:

   • Definition: Elimination, or excretion, is the removal of undigested and unabsorbed waste products from the body.

   • Function: The indigestible residues, along with water, are formed into feces and eliminated from the body through the rectum and anus, completing the digestive process.

What is peristalsis?

Peristalsis is a coordinated rhythmic contraction and relaxation of muscles that propels material through a tubular structure, such as the digestive tract. It is a vital physiological process that helps move ingested food, liquids, and other substances through various organs in the body.

What organs are involved in digestion and what does each do?

1. Mouth:

   • Function: The mouth is the beginning of the digestive system. Its functions include:

     • Ingestion: Taking in food.

     • Mechanical Digestion: Chewing breaks down food into smaller particles, increasing surface area.

     • Chemical Digestion: Salivary glands secrete saliva containing enzymes like amylase, initiating the breakdown of carbohydrates.

2. Esophagus:

   • Function: The esophagus is a muscular tube that transports food from the mouth to the stomach through a process called peristalsis. It doesn't participate in digestion but facilitates the movement of ingested food.

3. Stomach:

   • Function: The stomach performs several crucial functions, including:

     • Mechanical Digestion: Muscular contractions churn food, breaking it into smaller pieces.

     • Chemical Digestion: Gastric glands secrete gastric juice containing enzymes and hydrochloric acid to break down proteins.

     • Partial Nutrient Absorption: Some water, ions, and certain drugs are absorbed in the stomach.

4. Liver:

   • Function: The liver has multiple functions related to digestion, including:

     • Production of Bile: Bile aids in the emulsification and breakdown of fats.

     • Metabolism of Nutrients: Processes and regulates nutrients absorbed from the digestive tract.

     • Detoxification: Removes and processes toxins from the blood.

5. Gallbladder:

   • Function: The gallbladder stores and releases bile produced by the liver. It releases bile into the small intestine to aid in the digestion and absorption of fats.

6. Pancreas:

   • Function: The pancreas serves both endocrine and digestive functions, including:

     • Production of Digestive Enzymes: Pancreatic enzymes (lipase, amylase, protease) aid in the digestion of fats, carbohydrates, and proteins.

     • Release of Bicarbonate: Neutralizes acidic chyme from the stomach in the small intestine.

7. Small Intestine:

   • Function: The small intestine is the primary site for nutrient absorption and includes:

     • Final Digestion: Completion of digestion with the help of pancreatic enzymes.

     • Absorption: Nutrients (glucose, amino acids, fatty acids) are absorbed into the bloodstream.

     • Villi and Microvilli: Increase surface area for efficient absorption.

8. Large Intestine (Colon):

   • Function: The large intestine processes undigested food and absorbs water, electrolytes, and vitamins. It also forms and stores feces before elimination