Animal Physiology - Circulatory, Nervous, Digestive, and Respiratory Systems

"Describe the main theme of the animal circulatory system."

"The animal circulatory system is a vital transport network for oxygen, nutrients, waste, and other substances, consisting of blood, the heart, and blood vessels."

"Explain the composition of blood and its components."

"Blood is composed of various cell types including red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. Erythrocytes contain hemoglobin for oxygen transport, leukocytes are involved in the immune response, and platelets function in blood clotting."

"Define the role of red blood cells in the circulatory system."

"Red blood cells (erythrocytes) are numerous cells that contain hemoglobin, which binds oxygen in the lungs and releases it in capillaries. They lack nuclei in mature mammals."

"How does hemoglobin function in oxygen transport?"

"Hemoglobin consists of four polypeptide chains, each with a heme group containing iron, capable of binding O₂. It picks up oxygen in the lungs (forming oxyhemoglobin) and releases it in capillaries (forming deoxyhemoglobin), with binding dependent on the partial pressure of oxygen (Po₂)."

"Describe the function of white blood cells in the circulatory system."

"White blood cells (leukocytes) are typically larger than red blood cells, possess nuclei, and can migrate out of capillaries into tissue fluid. They are involved in the immune response and include granular and agranular types."

"What is the origin of blood cells in the body?"

"All blood cells originate from pluripotent stem cells in the bone marrow through a process called hematopoiesis."

"Explain the role of erythropoietin in blood cell production."

"Erythropoietin is a hormone that specifically stimulates the production of red blood cells."

"Describe the structure and function of the heart."

"The heart is a muscular organ responsible for pumping blood and contains two pairs of valves to ensure unidirectional blood flow."

"What are the types of valves in the heart and their functions?"

"The heart contains atrioventricular (AV) valves, which include the tricuspid (right) and bicuspid/mitral (left) valves that maintain flow between atria and ventricles, and semilunar valves, which include pulmonary and aortic valves that ensure one-way flow out of ventricles to arteries."

"How do the closing of heart valves contribute to heart sounds?"

"The closing of the atrioventricular (AV) valves produces the 'lub' sound, while the closing of the semilunar valves produces the 'dub' sound."

"Describe the function of the aorta and its branches."

"The aorta and its branches are systemic arteries that carry oxygen-rich blood from the left ventricle to the body."

"Explain how blood returns to the heart from the body."

"Blood returns to the right atrium via the superior vena cava from the upper body and the inferior vena cava from the lower body."

"Define the Central Nervous System (CNS)."

"The Central Nervous System (CNS) consists of the brain and spinal cord."

"What is the role of sensory neurons in the nervous system?"

"Sensory neurons, also known as afferent neurons, detect sensory input and carry signals to the CNS, serving as the body’s data collectors."

"How do motor neurons function in the nervous system?"

"Motor neurons, or efferent neurons, carry signals from the CNS to muscles and glands."

"Describe the Somatic Nervous System."

"The Somatic Nervous System controls voluntary movements by stimulating skeletal muscles."

"Explain the function of the Autonomic Nervous System."

"The Autonomic Nervous System controls involuntary movements such as heart rate, digestion, and respiratory rate by acting on smooth muscles, cardiac muscles, and glands."

"What is the role of the Sympathetic Nervous System (SNS)?"

"The Sympathetic Nervous System prepares the body for stress through the 'fight or flight' response, increasing heart rate, dilating pupils, and slowing digestion."

"Describe the function of the Parasympathetic Nervous System (PNS)."

"The Parasympathetic Nervous System calms the body through the 'rest and digest' response, slowing heart rate, stimulating digestion, and conserving energy."

"How do the sympathetic and parasympathetic systems work together?"

"The sympathetic and parasympathetic systems counterbalance each other to maintain homeostasis in the body."

"Define the Myelin Sheath and its function."

"The Myelin Sheath is produced by Schwann cells in the PNS and oligodendrocytes in the CNS, surrounding axons to insulate them and speed up signal transmission."

"What is gray matter composed of?"

"Gray matter is formed by dendrites and cell bodies in the CNS."

"Explain the concept of membrane potential in neurons."

"A potential difference exists across every cell’s plasma membrane, with the cytoplasmic side being negative and the extracellular fluid side positive."

"What is resting potential in a neuron?"

"Resting potential is the state when a neuron is not stimulated, typically around -70 mV, ranging from -40 to -90 millivolts."

"How does the sodium-potassium pump contribute to resting potential?"

"The sodium-potassium pump moves 3 Na⁺ ions out of the cell for every 2 K⁺ ions it brings in, contributing to the negative charge inside the cell."

"What role do ion leakage channels play in neuronal resting potential?"

"Ion leakage channels allow more K⁺ ions to diffuse out of the cell than Na⁺ ions to diffuse in, helping maintain the resting potential."

"Describe the composition of nerves in the PNS."

"In the PNS, myelinated axons are bundled together to form nerves."

"Describe the role of Excitatory Postsynaptic Potentials (EPSPs) in synaptic integration."

"EPSPs are depolarizing events that occur when sodium ions (Na⁺) influx into a neuron, making it more likely to fire an action potential."

"Explain the function of Inhibitory Postsynaptic Potentials (IPSPs)."

"IPSPs are hyperpolarizing events caused by chloride ions (Cl⁻) influx or potassium ions (K⁺) efflux, making a neuron less likely to fire."

"Define neurotransmitters and their role in the nervous system."

"Neurotransmitters are chemical messengers released at synapses that transmit signals between neurons and other cells."

"How does acetylcholine function at the neuromuscular junction?"

"Acetylcholine crosses the synapse between motor neurons and muscle fibers, binding to nicotinic receptors, opening ligand-gated Na⁺ channels, causing depolarization and muscle contraction."

"What terminates the action of acetylcholine in the synapse?"

"The action of acetylcholine is terminated by the enzyme acetylcholinesterase."

"Identify the major excitatory neurotransmitter in the central nervous system (CNS)."

"Glutamate is the major excitatory neurotransmitter in the CNS, involved in learning and memory, and produces EPSPs."

"List the major inhibitory neurotransmitters in the CNS and their effects."

"Glycine and GABA are the major inhibitory neurotransmitters in the CNS, opening Cl⁻ channels and producing IPSPs."

"Describe the functions of biogenic amines in the nervous system."

"Biogenic amines such as norepinephrine, dopamine, and serotonin are involved in alertness, motor control, reward, pleasure, sleep, mood, appetite, and intestinal health."

"What is the role of neuropeptides in the nervous system?"

"Neuropeptides like Substance P transmit pain signals, while enkephalins and endorphins act as natural painkillers by binding to opioid receptors."

"Explain the function of nitric oxide as a gasotransmitter."

"Nitric oxide causes smooth muscle relaxation and blood vessel dilation."

"Describe the evolution of the nervous system from sponges to more complex organisms."

"Sponges lack nerves, cnidarians have a simple nerve net, and free-living flatworms possess two nerve cords, representing the simplest associative activity."

"What is the main theme of the digestive system?"

"The digestive system breaks down food into smaller molecules for absorption into the bloodstream and eliminates waste."

"Define heterotrophs and their classification."

"Heterotrophs are animals that obtain their food from other organisms, classified as herbivores (plants), carnivores (animals), or omnivores (both)."

"Differentiate between intracellular and extracellular digestion."

"Intracellular digestion occurs inside individual cells using phagocytosis, while extracellular digestion occurs outside cells within a digestive cavity, involving hydrolysis reactions."

"What is the path of the vertebrate digestive system?"

"The path includes the mouth/pharynx (entry), esophagus (delivers food to stomach), stomach (preliminary digestion), small intestine (digestion and absorption), and large intestine (water and mineral absorption)."

"Describe the role of the small intestine in digestion."

"The small intestine receives chyme, digestive enzymes, and bicarbonate from the pancreas, and bile from the liver/gallbladder. Its epithelial wall has villi covered in microvilli, forming a dense brush border that greatly increases surface area for absorption."

"Explain how amino acids and sugars are processed after absorption in the small intestine."

"Amino acids and sugars are absorbed in the small intestine and then processed by the liver, which stores excess sugars as glycogen or releases glucose to maintain blood glucose levels."

"How do fatty acids and monoglycerides get absorbed in the small intestine?"

"Fatty acids and monoglycerides diffuse into epithelial cells, reassemble into triglycerides, and are packaged into chylomicrons. This process is aided by the emulsification of fats by bile salts and breakdown by pancreatic lipase."

"Define the function of the pancreas in digestion."

"The pancreas secretes pancreatic fluid into the duodenum via the pancreatic duct, containing enzymes like Trypsin, Chymotrypsin, Pancreatic Amylase, and Lipase. It also secretes bicarbonate to neutralize acidic chyme and functions as both an exocrine and endocrine gland."

"Explain the role of the liver in digestion and metabolism."

"The liver is the body's largest internal organ, secreting bile for emulsifying fats, chemically modifying absorbed substances, removing toxins, regulating steroid hormones, and producing plasma proteins such as albumin and clotting factors."

"Describe the function of the gallbladder in the digestive process."

"The gallbladder stores and concentrates bile, releasing it into the duodenum when fatty food is detected, triggered by its contraction."

"How is digestion regulated in the body?"

"Digestion is regulated by the nervous and endocrine systems. The nervous system stimulates salivary and gastric secretions through sensory inputs, while hormones like gastrin, CCK, secretin, and GIP coordinate digestive activities."

"What is the role of gastrin in digestion?"

"Gastrin is released by the stomach in response to protein intake, triggering the secretion of hydrochloric acid (HCl) and pepsinogen to aid in digestion."

"Explain the function of cholecystokinin (CCK) in digestion."

"CCK inhibits gastric motility, stimulates gallbladder contraction to release bile, and promotes pancreatic enzyme secretion."

"Describe the role of secretin in the digestive process."

"Secretin inhibits gastric activity and stimulates the secretion of bicarbonate from the pancreas to neutralize stomach acid."

"How does the body regulate blood glucose levels after a meal?"

"After a meal, high blood sugar levels trigger insulin release, which stimulates the liver and muscles to store glucose as glycogen."

"What happens to blood glucose levels when they are low?"

"When blood glucose levels are low, glucagon is released, stimulating the liver to break down glycogen (glycogenolysis) or convert other molecules to glucose (gluconeogenesis)."

"Describe the process of inhalation."

"Inhalation involves the contraction of external intercostal muscles and the diaphragm, which increases thoracic volume, expands the thoracic cavity, lowers internal pressure, and draws air into the lungs."

"Explain the role of elasticity in exhalation."

"Elasticity allows for passive exhalation by enabling the thorax and lungs to return to their resting shape, which helps push air out of the lungs."

"Define Tidal Volume (TV)."

"Tidal Volume (TV) is the volume of air inhaled or exhaled during normal breathing at rest, typically around 500 mL."

"What is Vital Capacity (VC) and why is it important?"

"Vital Capacity (VC) is the maximum amount of air that can be forcibly exhaled after a deep breath, reflecting lung strength and elasticity."

"How does hypoventilation affect blood Pco₂ levels?"

"Hypoventilation leads to insufficient breathing, resulting in elevated blood Pco₂ levels."

"Describe the effects of hyperventilation on blood Pco₂."

"Hyperventilation causes excessive breathing, which results in decreased blood Pco₂ levels."

"Explain how respiration is controlled in the body."

"Respiration is controlled by neurons in the respiratory control center located in the medulla oblongata, which stimulate respiratory muscles for inhalation and relaxation for exhalation."

"How can breathing be voluntarily overridden?"

"Breathing is usually automatic but can be voluntarily overridden by conscious control, allowing for changes in breathing patterns."

"What triggers an increase in breathing rate?"

"An increase in blood Pco₂ levels raises carbonic acid, lowers blood pH, and is detected by chemosensitive neurons, which send impulses to the medulla to increase the breathing rate."