Respiratory System Flashcards
What is the function of the medulla oblongata?
The medulla oblongata relays motor and sensory impulses between other parts of the brain and contains visceral centers.
What is the function of the pons?
The pons acts as a bridge, relaying sensory information between the cerebellum and the brainstem.
What is the function of the midbrain?
The midbrain controls visual and auditory reflexes from the corpora quadrigemina and automatic behaviors necessary for survival.
What is the function of the thalamus?
The thalamus is where nearly all communication to the cerebral cortex must pass through.
What is the function of the hypothalamus?
The hypothalamus functions to regulate body temperature, hunger, and thirst.
What is the function of the cerebellum?
The cerebellum smooths and coordinates body movements.
What is the function of the cerebrum?
The cerebrum is responsible for logical thought and conscious awareness of the environment.
What is the function of the cerebral cortex?
The cerebral cortex is the home of the conscious mind.
What is the function of the precentral gyrus?
The precentral gyrus controls voluntary motor functions.
What is the function of the postcentral gyrus?
The postcentral gyrus receives somatic sensory information.
What is the function of the limbic system?
The limbic system contains structures that regulate and cause emotional responses.
What is the function of the reticular activating system?
The reticular activating system is responsible for the arousal of the brain.
What are the functions of the spinal cord?
The spinal cord functions in conduction and reflexes.
What is the function of sensory nerves?
Sensory nerves contain only sensory axons and take information to the central nervous system.
What is the function of motor nerves?
Motor nerves contain only motor axons and take information away from the central nervous system.
What does the cervical plexus serve?
The cervical plexus serves the head, neck, and shoulders.
What does the brachial plexus serve?
The brachial plexus is the major nerve plexus for the upper limbs.
What does the lumbar plexus serve?
The lumbar plexus serves the pelvic and anterior leg.
What does the sacral plexus serve?
The sacral plexus serves the posterior leg.
What is the function of chordae tendineae?
Chordae tendineae are strong bands that connect the papillary muscles to the heart valves, preventing prolapse.
What is the general function of heart valves?
Heart valves prevent the backflow of blood.
What is the function of the sinoatrial (SA) node?
The SA node is the electrical event that begins each heartbeat.
What is the function of the atrioventricular (AV) node?
The AV node can have its own impulses, but when connected, impulses are delayed, causing ventricular contraction.
What is the function of Purkinje fibers?
Purkinje fibers lie in the ventricle walls and cause the final part of ventricular contraction.
What are arteries?
Arteries are vessels that take blood away from the heart.
What are veins?
Veins take blood to the heart.
What is the function of muscular arteries?
Muscular arteries regulate blood flow to organs or organ parts.
What are elastic arteries?
Elastic arteries are the largest arteries next to the heart, filled with elastic fibers.
What is pulmonary ventilation?
Pulmonary ventilation is the movement of air in and out of the lungs.
What is external respiration?
External respiration is gas exchange at the lungs.
What is internal respiration?
Internal respiration is gas exchange at the capillary beds of the systemic circuits.
What is hepatic portal blood?
Hepatic portal blood is deoxygenated, nutrient-rich blood that goes to the liver.
What is the vestibule?
The vestibule is the area where both the urethra and vagina open.
What is ingestion?
Ingestion is the intake of food.
What is propulsion in the GI tract?
Propulsion is the movement of substances through the GI tract by peristalsis.
What is mechanical digestion?
Mechanical digestion is the breakdown of food into smaller parts by mechanical means.
What is chemical digestion?
Chemical digestion is the breakdown of food by enzymes.
What is absorption in the GI tract?
Absorption is the movement of nutrients into our capillary beds or lymphatic system.
What is the pleura?
The pleura are the serous membranes of the lungs.
What is the mediastinum?
The mediastinum is the middle section of the thoracic cavity containing the heart.
What is peristalsis?
Peristalsis is used for propulsion in the gastrointestinal tract by the layers of smooth muscle.
What is segmentation?
Segmentation is used for mechanical digestion and mixes substances in the GI tract.
What is the peritoneum?
The peritoneum is the serous membrane in the abdominal cavity.
What is the mesentery?
The mesentery is a double layer of peritoneum.
What is the serosa of an organ?
The serosa refers to the outside layer of organs within the peritoneal cavity, also known as the visceral peritoneum.
What is the adventitia?
The adventitia is the outer layer of organs outside the peritoneal cavity.
What is the function of the pyloric sphincter?
The pyloric sphincter controls the release of substances from the stomach into the duodenum.
What is the function of the teniae coli?
The teniae coli are thickenings of the longitudinal muscle in the large intestine that cause puckering called haustra.
What are haustra?
Haustra are the puckering found in the colon.
What is the urinary trigone?
The urinary trigone is the triangular region of the bladder where the ureters enter and the urethra exits.
What is the renal medulla?
The renal medulla is the inner region of the kidney that contains all the pyramids.
What are the renal columns?
The renal columns are projections of the cortex in between the renal pyramids.
What is the renal cortex?
The renal cortex is the outside region of the kidney where most of the body's blood is found.
What is the function of the minor and major calyces?
Minor and major calyces collect urine from the nephrons and funnel it to the renal pelvis.
What is the function of the renal pelvis?
The renal pelvis functions to collect urine from the major calyces and send it to the ureter.
What is the detrusor muscle?
The detrusor muscle is the thick muscle in the bladder wall responsible for contraction during urination.
What is the function of the epiglottis?
The epiglottis routes food and air to their proper channels, preventing food from entering the trachea.
What is the function of the trachea?
The trachea is the windpipe, serving as a passageway for air to the lungs.
What are the functions of the primary, secondary, and tertiary bronchi?
Primary bronchi serve each lung, secondary bronchi serve each lobe, and tertiary bronchi serve each segment of the lungs.
What is the function of the alveoli?
The alveoli are the actual locations within the lungs where gas exchange occurs.
What is the function of the mucosal nerve plexus?
The mucosal nerve plexus functions for the mucosal smooth muscle and gland secretions.
What is the function of the myenteric nerve plexus?
The myenteric nerve plexus functions to control peristalsis and segmentation in the GI tract.
What is the function of ameloblasts?
Ameloblasts function to deposit enamel buds.
What is the function of odontoblasts?
Odontoblasts secrete and maintain dentin.
What is the function of cementoblasts?
Cementoblasts produce cementum.
What is the function of the periodontal ligament?
The periodontal ligament consists of collagen fibers that run from the cementum to the bone, anchoring the tooth.
What is cementum?
Cementum is the calcified connective tissue that attaches the tooth to the periodontal ligament.
What is the function of the esophagus?
The esophagus collects food from the pharynx and sends it to the stomach.
What are rugae?
Rugae are the ridges in the stomach that flatten as the stomach fills.
What is the function of the ileum?
The ileum is the largest region of the small intestine where most absorption occurs.
What is the function of the large intestine?
The large intestine functions for water and electrolyte absorption.
What are the digestive functions of the pancreas?
The pancreas makes enzymes and bicarbonate juices used for digestion.
What is the main site of nutrient absorption and digestion?
The small intestine is the main site of nutrient absorption and digestion.
What is the function of circular folds, villi, and microvilli?
Circular folds, villi, and microvilli function to increase the surface area of the small intestine for absorption.
What is the function of the stomach in mechanical digestion?
The stomach turns food into a paste by mechanical means.
What do parietal cells secrete?
Parietal cells secrete hydrochloric acid and intrinsic factor.
What do chief cells secrete?
Chief cells secrete pepsinogen.
What do enteroendocrine cells in the small intestine secrete?
Enteroendocrine cells in the small intestine secrete hormones like cholecystokinin (CCK) and secretin, which signal the gallbladder and pancreas.
What do enteroendocrine cells in the stomach secrete?
Enteroendocrine cells in the stomach secrete gastrin.
What is the function of absorptive cells?
Absorptive cells function to uptake digested nutrients.
What do the crypts of Lieberkühn secrete?
The crypts of Lieberkühn contain epithelial cells that secrete intestinal juices.
What do Paneth cells secrete?
Paneth cells secrete enzymes that destroy certain bacteria.
What are Peyer's patches?
Peyer's patches are aggregated areas of lymphatic tissue in the small intestine.
What do Brunner's glands secrete?
Brunner's glands secrete a bicarbonate-rich mucus.
What is the function of the gallbladder?
The gallbladder stores bile.
What is the function of the liver in digestion?
The liver makes and secretes bile, which aids in fat emulsification.
What is the function of the appendix?
The appendix functions to neutralize pathogens.
What are Kupffer cells?
Kupffer cells are macrophages in the liver that kill bacteria and foreign objects.
What is the function of the duodenum?
The duodenum receives chyme from the stomach and is the site of action for liver and pancreas secretions.
What do the parotid salivary glands produce?
The parotid salivary glands secrete enzymes in saliva.
What do the sublingual salivary glands produce?
The sublingual salivary glands produce mostly mucous saliva.
What do the submandibular salivary glands produce?
The submandibular salivary glands produce both serous and mucous saliva.
What is the function of the kidney?
The kidney makes urine.
What is the function of the nephron?
The nephron is the microscopic structure responsible for making urine.
What is the function of the ureter?
The ureter transports urine from the kidney to the bladder.
What is the function of the bladder?
The bladder functions to store and expel urine.
What is the function of the urethra?
The urethra propels urine to the outside.
What is the function of interstitial cells (Leydig cells)?
Interstitial cells produce testosterone.
What is the function of myoid cells?
Myoid cells help deliver sperm to the epididymis by contracting sperm out of the seminiferous tubules.
What is the function of Sertoli cells?
Sertoli cells surround spermagonia and form the blood-testes barrier.
What are the primary male sex organs and why?
The testes are the primary male sex organs because they produce sperm and secrete testosterone.
What is the function of the epididymis?
The epididymis is the organ where sperm mature.
What is the function of the ductus deferens (vas deferens)?
The ductus deferens stores and transports sperm.
What is the ejaculatory duct?
The ejaculatory duct is where sperm and seminal fluid mix.
What is the function of the prostate gland?
The prostate gland secretes seminal fluid and is located just inferior to the bladder.
What is the function of the bulbourethral glands?
The bulbourethral glands secrete pre-seminal fluid, which lubricates and eliminates traces of acid from urine.
What do the seminal vesicles produce?
The seminal vesicles secrete the majority of seminal fluid and are located on the posterior side of the bladder.
What is the penis?
The penis is the male reproductive organ for the delivery of sperm.
What are the seminiferous tubules?
The seminiferous tubules are the actual sperm factories.
What is the primary female sex organ and why?
The ovary is the primary female sex organ because it produces eggs and estrogen.
What is the function of the uterine tube (fallopian tube)?
The uterine tube is where fertilization occurs.
What is the function of the fimbriae?
The fimbriae are finger-like projections that sweep the egg into the uterine tube.
What is the ampulla of the uterine tube?
The ampulla is the middle portion of the uterine tube where fertilization specifically occurs.
What is the function of the uterus?
The uterus is where the fetus develops.
What is the cervix?
The cervix is the neck of the uterus and is blocked during fetal development for protection.
What is the ovarian cycle?
The ovarian cycle is the cycle of the ovary that causes the development of the egg.
What is the uterine cycle?
The uterine cycle is the cycle of the uterus that prepares for fetal implantation.
What are the main parts of the diencephalon?
The main parts of the diencephalon are the hypothalamus, thalamus, and epithalamus.
What are the main parts of the brainstem?
The main parts of the brainstem are the midbrain, pons, and medulla oblongata.
Where are the cell bodies of sensory neurons located?
The cell bodies of sensory neurons are located in the dorsal root ganglia, external to the spinal cord.
Where are the cell bodies of somatic motor neurons located?
The cell bodies of somatic motor neurons are located in the ventral horn of the spinal cord.
Where are the cell bodies of interneurons located?
Interneurons are located in the posterior horn of the spinal cord.
Where are the cell bodies of preganglionic autonomic neurons located?
Preganglionic autonomic cell bodies are located in the lateral horn of the spinal cord.
Where are the cell bodies of postganglionic autonomic neurons located?
Postganglionic autonomic cell bodies are located in autonomic ganglia.
Describe the pathway of cerebral cortex information processing.
Sensory information is received by the primary sensory cortex, then goes to the sensory association area, then to the multimodal association area, then to the premotor cortex, and finally to the primary motor cortex.
What is the function of the dorsal column pathway?
The dorsal column pathway is for fine touch and pressure.
What is the function of the lateral spinothalamic pathway?
The lateral spinothalamic pathway deals with pain and temperature.
What is the function of the spinocerebellar pathways?
The spinocerebellar pathways are for proprioception (detecting stretch in muscles and ligaments).
What is the function of the ventral spinothalamic pathway?
The ventral spinothalamic pathway is for crude touch and pressure.
Name the descending motor pathways.
The descending motor pathways include the pyramidal pathway and the extrapyramidal pathways (tectospinal, vestibulospinal, rubrospinal, and reticulospinal).
Name the layers of the meninges from superficial to deep.
The layers of the meninges from superficial to deep are the dura mater (periosteal and meningeal layers), arachnoid mater, and pia mater.
What is located in the subdural space?
The subdural space contains venous blood.
What is located in the subarachnoid space?
The subarachnoid space contains cerebrospinal fluid (CSF).
What is the function of the vagus nerve?
The vagus nerve (cranial nerve X) is unique as it extends below the neck region, serving various organs in the thorax and abdomen.
What are the general functions of the sympathetic nervous system?
Sympathetic responses generally increase blood glucose, divert blood away from the GI tract and urinary system, increase heart rate and blood pressure, and decrease peristalsis.
What does the somatic division of the nervous system innervate?
The somatic division innervates motor neurons to skeletal muscles.
What does the autonomic nervous system (ANS) innervate?
The ANS innervates cardiac muscle, smooth muscle, and glands.
Compare the preganglionic fiber lengths of the sympathetic and parasympathetic nervous systems.
Preganglionic parasympathetic fibers are long, while preganglionic sympathetic fibers are shorter.
Compare the postganglionic fiber lengths of the sympathetic and parasympathetic nervous systems.
Postganglionic parasympathetic fibers are short, while postganglionic sympathetic fibers are longer.
What is the role of the adrenal medulla?
The adrenal medulla secretes large amounts of epinephrine and norepinephrine into the bloodstream.
What is the order of white blood cells from most abundant to least abundant?
Neutrophils, lymphocytes, monocytes, eosinophils, basophils (Never Let Monkeys Eat Bananas).
What is the function of neutrophils?
Neutrophils are leukocytes responsible for destroying bacteria.
What is the function of eosinophils?
Eosinophils are involved in ending allergic reactions and parasitic infections.
What is the function of basophils?
Basophils are cell mediators of inflammation, similar to mast cells.
What is the function of lymphocytes?
Lymphocytes are B and T cells involved in the immune response.
What is the function of monocytes?
Monocytes change into macrophages for non-specific phagocytosis.
Describe the layers of a centrifuged blood sample.
Plasma is the top layer (about 55%), the buffy coat (leukocytes and platelets) is the middle layer (less than 1%), and the hematocrit (erythrocytes) is the bottom layer.
Why are white blood cells considered 'true cells'?
White blood cells are considered true cells because they possess a nucleus.
What chamber receives blood from the pulmonary system?
The left atrium receives oxygenated blood from the pulmonary system via the pulmonary veins.
What chamber pumps blood into the aorta?
The left ventricle pumps oxygenated blood into the aorta.
What chamber receives blood from the systemic circulation?
The right atrium receives deoxygenated blood from the systemic circulation via the vena cavae.
What chamber pumps blood into the pulmonary artery?
The right ventricle pumps deoxygenated blood into the pulmonary artery.
What is the structure of the mitral (bicuspid) valve?
The mitral valve has two cusps.
What is the structure of the tricuspid, aortic, and pulmonary valves?
The tricuspid, aortic, and pulmonary valves each contain three cusps.
Why is the left ventricle the largest ventricle?
The left ventricle is the largest because it must pump blood throughout the entire systemic circuit, which is longer and has more resistance.
What are pectinate muscles?
Pectinate muscles are horizontal ridges found in the atria.
What are trabeculae carneae?
Trabeculae carneae are irregular ridges of muscle found in the ventricles.
What is the function of the fibrous pericardium?
The fibrous pericardium is the tough outer layer that protects and anchors the heart.
What is the function of the serous pericardium?
The serous pericardium consists of two layers (parietal and visceral) that produce pericardial fluid to reduce friction.
What is the epicardium?
The visceral layer of the serous pericardium is also known as the epicardium.
What is the myocardium?
The myocardium is the cardiac muscle layer of the heart wall.
What is the endocardium?
The endocardium is the endothelial layer that lines the heart chambers and valves.
How does the sympathetic nervous system affect the heart?
The sympathetic nervous system increases the force and rate of heart contraction.
How does the parasympathetic nervous system affect the heart?
The parasympathetic nervous system controls the rate of the SA and AV nodes.
What supplies blood to the heart muscle?
The coronary arteries supply blood to the heart muscle.
How does blood drain from the heart muscle?
Blood drains from the heart muscle via the great cardiac vein, middle cardiac vein, or small cardiac vein into the coronary sinus, which then empties into the right atrium.
What is the function of the foramen ovale in fetal circulation?
The foramen ovale allows blood to bypass the right ventricle and go directly from the right atrium to the left atrium.
What is the function of the ductus arteriosus in fetal circulation?
The ductus arteriosus allows blood to bypass the lungs by shunting blood from the pulmonary artery to the aorta.
What is the function of the ductus venosus in fetal circulation?
The ductus venosus bypasses the liver, allowing oxygenated blood from the umbilical vein to flow directly into the inferior vena cava.
What are the three tunics of blood vessels?
The three tunics are the tunica intima, tunica media, and tunica adventitia.
Which tunic is largest in arteries?
The tunica media is the largest tunic in arteries, containing smooth muscle and elastic fibers.
Which tunic is largest in veins?
The tunica adventitia is often the largest tunic in veins, providing structural support.
Where is oxygenated blood found in the circulatory system?
Oxygenated blood is found in the left side of the heart, pulmonary veins, and systemic arteries.
Where is deoxygenated blood found in the circulatory system?
Deoxygenated blood is found in the right side of the heart, pulmonary arteries, and systemic veins.
How is lymph propelled through the lymphatic system?
Lymph is propelled by the contraction of skeletal muscles, the pulsing of arteries, and movements of the body.
What is the pathway of lymph flow?
Lymph flows from capillaries to collecting vessels, then to trunks, then to ducts, and finally to the blood.
What does the right lymphatic duct drain?
The right lymphatic duct drains the superior right quadrant of the body.
What does the thoracic duct drain?
The thoracic duct drains the other three-fourths of the body.
How do the right and left lungs differ in structure?
The right lung has two fissures and three lobes, while the left lung has one fissure and two lobes.
What muscles are involved in normal inspiration?
Normal inspiration involves the contraction of the diaphragm and external intercostal muscles.
What muscles are involved in normal expiration?
Normal expiration is a passive process involving the relaxation of the diaphragm and external intercostal muscles.
What muscles are involved in forced inspiration?
Forced inspiration involves accessory muscles such as the sternocleidomastoid, scalenes, and pectoralis muscles.
What muscles are involved in forced expiration?
Forced expiration involves the abdominal muscles.
How are volume and pressure related during breathing?
During inspiration, the thoracic cavity volume increases, pressure decreases, and air moves in. During expiration, the thoracic cavity volume decreases, pressure increases, and air moves out.
What is the function of the thyroid cartilage?
The thyroid cartilage is the largest laryngeal cartilage and contains the laryngeal prominence (Adam's apple).
What is the function of the cricoid cartilage?
The cricoid cartilage forms a complete ring and is the inferior-most cartilage of the larynx.
What is the function of the arytenoid cartilages?
The arytenoid cartilages hold the vocal cords in place and move them to produce sound.
What are the general functions of respiration?
The general functions of respiration include pulmonary ventilation, external respiration, transport of respiratory gases, and internal respiration.
Where does starch digestion begin?
Starch digestion begins in the mouth.
Where does protein digestion begin?
Protein digestion begins in the stomach.
Where does most chemical digestion and absorption occur?
Most chemical digestion and absorption occur in the small intestine.
What structures are located in the nasopharynx?
The nasopharynx contains the pharyngeal tonsils and the tubal tonsils, and the pharyngeal-tympanic tube.
What structures are located in the oropharynx?
The oropharynx contains the palatine tonsils and the lingual tonsils.
What is the function of the pharyngeal-tympanic tube?
The pharyngeal-tympanic tube connects the nasopharynx to the middle ear, equalizing pressure.
Where are Peyer's patches located?
Peyer's patches are located in the small intestine.
What do the crypts of Lieberkühn secrete?
The crypts of Lieberkühn secrete intestinal juices.
What do Brunner's glands secrete?
Brunner's glands secrete a bicarbonate-rich mucus in the duodenum.
What are the functions of incisor teeth?
Incisor teeth are used for cutting and tearing off pieces of food.
What are the functions of molar and premolar teeth?
Molar and premolar teeth are used for grinding food.
What are the parts of the large intestine?
The parts of the large intestine include the cecum, appendix, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anal canal.
What are the hepatic and splenic flexures?
The hepatic flexure is the bend between the ascending and transverse colon, and the splenic flexure is the bend between the transverse and descending colon.
What is the structure of a tooth's crown?
The crown of a tooth is the visible part, covered by enamel, the hardest substance in the body.
What are the five stages of digestion?
The five stages of digestion are ingestion, propulsion, mechanical digestion, chemical digestion, absorption, and defecation.
How does the liver participate in digestion?
The liver secretes bile, which emulsifies fats, aiding in their digestion.
How does the pancreas participate in digestion?
The pancreas secretes digestive enzymes and bicarbonate juices into the small intestine.
What is the pathway of bile flow?
Bile flows from the right and left hepatic ducts to the common hepatic duct, then to the common bile duct, which enters the duodenum.
What are the three types of capillaries in the urinary system?
The three types are glomerular capillaries (filtration), peritubular capillaries, and vasa recta (secretion and reabsorption).
What are the three processes of urine formation?
The three processes are filtration (glomerulus to capsule), reabsorption (tubules to blood), and secretion (blood to tubules).
Where is stratified ciliated columnar epithelium found?
Stratified ciliated columnar epithelium is found in the respiratory system.
Where is transitional epithelium found?
Transitional epithelium is found in the urinary system, specifically the bladder and ureters.
Where is stratified squamous epithelium found?
Stratified squamous epithelium is found in the openings of the digestive tube and areas of voluntary swallowing.
What is the sequence of blood flow through the kidney's arteries?
Renal artery -> segmental arteries -> interlobar arteries -> arcuate arteries -> cortical radiate arteries -> afferent arterioles -> glomerulus -> efferent arterioles -> peritubular capillaries/vasa recta.
What is the sequence of blood flow through the kidney's veins?
Peritubular capillaries/vasa recta -> cortical radiate veins -> arcuate veins -> interlobar veins -> renal vein.
What is normally found in urine?
Urea, uric acid, and creatinine are normally found in urine. Glucose is typically absent.
What is the pathway of urine flow?
Collecting ducts -> minor calyx -> major calyx -> renal pelvis -> ureter -> bladder -> urethra.
What is the pathway through the nephron?
Glomerular capsule -> proximal convoluted tubule -> loop of Henle -> distal convoluted tubule -> collecting duct.
Compare the internal and external urethral sphincters.
The external urethral sphincter is skeletal muscle, located in the urogenital diaphragm, and voluntarily controlled. The internal urethral sphincter is smooth muscle, located at the bladder-urethra junction, and involuntarily controlled.
What is the order of sperm development?
Spermatogonia -> primary spermatocytes -> secondary spermatocytes -> spermatids -> sperm.
What is the order of egg development?
Primordial follicles -> primary follicles -> secondary follicles -> vesicular (Graafian) follicle containing the mature oocyte.
What are the phases of the uterine cycle?
The phases are menstruation, proliferative phase, and secretory phase.
What are the phases of the ovarian cycle?
The phases are follicular, ovulation, and luteal.
What happens during the proliferative phase of the uterine cycle?
The endometrium rebuilds after menstruation.
What happens during the secretory phase of the uterine cycle?
The endometrium prepares for implantation.
What is the role of luteinizing hormone (LH) in the female cycle?
LH is important for triggering ovulation.
What is the role of follicle-stimulating hormone (FSH) in the female cycle?
FSH stimulates the development of ovarian follicles.
Where does implantation occur?
Implantation occurs in the uterus.
Where does fertilization occur?
Fertilization occurs in the ampulla of the uterine tube.
Where does sperm production begin?
Sperm production begins in the seminiferous tubules.
Where do sperm mature and become motile?
Sperm mature and become motile in the epididymis.
What are the primary sex organs and why?
The testes and ovaries are the primary sex organs because they produce gametes (sperm and eggs) and sex hormones (testosterone and estrogen).
What are the three named regions of the male urethra?
The three regions are the prostatic urethra, membranous urethra, and penile (spongy) urethra.
What is the pathway of sperm?
Seminiferous tubules -> straight tubules -> rete testis -> efferent ductules -> epididymis -> ductus deferens -> ejaculatory duct -> prostatic urethra -> membranous urethra -> penile urethra -> external urethral orifice.