Exam 4 PP Material Flashcards
(159 cards)
1
Q
What is a hormone?
A
Hormones are chemical messengers secreted into the bloodstream by endocrine glands and specialized cells in tissues that stimulate responses in distant targets.
2
Q
What is the endocrine system?
A
This is a system of communication that uses hormones. This system is crucial in the maintenance of homeostasis.
3
Q
What is the difference between endocrine and exocrine glands?
A
Endocrine glands are ductless and secrete internally into the blood.
Exocrine glands secrete substances through ducts onto the body surface.
4
Q
What is the anatomy of the pituitary gland?
A
The pituitary gland has two parts: adenohypophysis and neurohypophysis.
Adenohypophysis- anterior lobe and pars tuberalis. Here, acidophils and basophils secrete hormones. Hypophyseal portal system present here as well.
Neurohypophysis- posterior lobe with the stalk (infundibulum) and median eminence. Consists of nervous tissue that includes axons of hypothalamic neurons from the hypothalamo-hypophyseal tract.
5
Q
How is the pituitary gland related to the hypothalamus?
A
The hypophyseal portal system in adenohypophysis portion of pituitary gland is the blood vessel connection to the hypothalamus.
6
Q
What is the location of the pituitary gland?
A
The pituitary gland (hypophysis) hangs below the hypothalamus into the sella turcica of the sphenoid bone. The anterior portion (adenohypophysis) is connected to the hypothalamus by blood vessels of the hypophyseal portal system. The posterior part (neurohypophysis) is connected to hypothalamus via the infundibulum.
7
Q
How does the hypothalamus control pituitary function?
A
Hormones secreted by the hypothalamus travel through the hypophyseal portal system to either stimulate or inhibit release of pituitary hormones from the adenohypophysis.
8
Q
What are the hormones produced by the two lobes of the pituitary gland?
A
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Thyroid-stimulating hormone (TSH)
- Adrenocorticotropic hormone (ACTH)
- Prolactin (PRL)
- Growth hormone (GH)
- Antidiuretic hormones (ADH)
- Oxytocin (OT)
9
Q
What is the function of Follicular-stimulating hormone (FSH)?
A
Functions: growth of ovarian follicles and secretion of estrogen in females. sperm production in males.
Target: Ovaries, testes
10
Q
What is the function of Luteinizing hormone (LH)?
A
Functions: ovulation, production and maintenance of corpus luteum in females. testosterone secretion in males.
Targets: Ovaries, testes
11
Q
What is the function of Thyroid-stimulating hormone (TSH)?
A
Functions: growth of thyroid and secretion of thyroid hormone
Target: thyroid gland
12
Q
What is the function of Adrenocorticotropic hormone (ACTH)?
A
Functions: growth of adrenal cortex and secretion of glucocorticoids
Target: Adrenal cortex
13
Q
What is the function of Prolactin (PRL)?
A
Functions: milk synthesis in females. Increased LH sensitivity and testosterone secretion in males.
Target: mammary glands, testes
14
Q
What is the function of growth hormone (GH)?
A
Function: widespread tissue growth especially in stated tissues.
Targets: liver, bone, cartilage, muscle, and fat.
15
Q
What is the function of antidiuretic hormone (ADH)?
A
Functions: Water retention
Targets: kidneys
16
Q
What is the function of oxytocin (OT)?
A
Functions: labor contractions, milk release, ejaculation, sperm transport in female, sexual affection, parent-offspring bonding
Targets: Uterus, mammary glands, and brain
17
Q
What are the major organs of the endocrine system?
A
Pineal gland, hypothalamus, pituitary gland, thyroid gland, thymus, adrenal gland, pancreas, parathyroid glands, ovaries and testes.
18
Q
Identify the portions of the hypophysis that arose from the roof of the oral cavity.
A
B and C
19
Q
The hormone vasopressin is released from which specific region of the hypophysis?
A
Pars nervosa
20
Q
Which region of the suprarenal gland manufactures and secretes epinephrine?
A
Medulla
21
Q
Identify region D.
A
Isthmus of the thyroid
22
Q
Which of the following cells secretes calcitonin?
A
Parafollicular cells of the thyroid
23
Q
Identify the endocrine glands indicated as A.
A
Parathyroids
24
Q
Which region of the hypophysis secretes hormones that effect the testis and ovaries?
A
Pars distalis
25
Which of the cell indicated secretes the hormone that lowers blood sugar?
A
26
Thyroid hormones T3 and T4 are stored in which of the following?
Colloid
27
Melatonin is secreted by which of the following endocrine glands?
Pineal gland
28
What is the difference between respiration, breathing, and cellular respiration?
29
What is the function of the respiratory system?
Gas exchange, speech, small control pH of body, aid in BP regulation by assisting angiotensin II production, creates pressure gradients for flow of lymph and venous blood, and holding breath helps expel waste.
30
What are the different zones of the respiratory system?
1. Conducting zone- passages fro air flow but not exchange of gases
2. Respiratory zone- gas exchange area
3. Upper respiratory tract- nose through larynx
4. Lower respiratory tract- trachea through lungs
31
What is included in the upper respiratory tract?
Respiratory organs of the head and neck extending from the nose through the larynx.
32
Label and know the structures of the conducting portion of the respiratory system?
Nasal cavity, frontal sinus, sphenoidal sinus, pharynx, larynx, trachea, bronchi, lung, and bronchiole.
33
Identify and describe the function of the paranasal sinuses. Where do they open into the nasal cavity?
The sinuses humidify the inhaled air and contain cells that participate in the immune system response. In addition, the sinuses are air-filled spaces that significantly decrease the weight of the head and impact the resonance of the human voice.
34
Label the structures of the conducting portion of the pharynx.
The pharynx is a muscular funnel extending from the choanae to the larynx.
35
Label structures of the conducting portion of the larynx (specifically the structures responsible for spoken language).
The larynx is also called the voice box. The superior opening is the glottis and is guarded by a flap called the epiglottis. The thyroid cartilage covers the anterior and lateral aspects of the larynx. Inferior to that is the cricoid cartilage that connects the larynx to the trachea.
36
What are the functions and major processes of the digestive system?
The primary purpose is to break food into forms that can be used by cells and to absorb nutrients so they can be distributed to tissues. Involved ingestion, digestion, absorption, compaction, and defecation.
37
What are the accessory organs of the digestive system?
Accessory organs include teeth, tongue, salivary glands, liver, gallbladder, and pancreas.
38
What are the layers of the wall of the digestive tract?
The layers of the walls from inner to outer are muscoa, submucosa, muscularis externa, and serosa.
39
What is the enteric nervous system?
The enteric nervous system is the GIT's own nervous system. It supplies the esophagus, stomach, and intestines. It controls peristalsis (contractions of muscularis externis), and glandular secretions of the mucosa. Sensory information here is carried to CNS via the vagus nerve.
40
What are the different mesenteries and how do they relate to digestive system?
Mesenteries are connective tissue sheets that hold the abdominal viscera in place.
The lesser omentum extends from the lesser curvature of the stomach to the liver. The greater omentum hangs down like an apron from the stomach's greater curvature. The mesocolon is the mesentary of the colon.
41
What is the role of the teeth, tongue, and other organs of the oral cavity?
The tongue takes food in, helps teeth masticate, and compresses food into a bolus. Tongue has taste buds and initiates swallowing.
The teeth masticate food.
Salivary glands is water and mucus and enzymes that lubricate food and starts to digest starch and kills bacteria.
42
What are the names and locations of the salivary glands?
There are 3 extrinsic salivary glands. Parotid (duct opens at 2nd upper molar), submandibular (duct opens at lower central incisors), and sublingual (several openings underneath tongue)
43
What is the function and location of pharyngeal constrictor muscles?
Activation of these muscles constricts the airway which assists in swallowing.
44
What is the histology of the esophagus?
The mucosa of the esophagus consists of nonkeratinized stratified squamous epithelium.
45
Which layer of the tubular gastrointestinal tract wall is responsible for peristalsis?
Muscularis Externa
46
Which of the following mineralized tissues covers the root of the tooth?
Cementum
47
Which of the following structures, increasing surface area of the tubular gastrointestinal tract, do NOT protrude into the lumen?
Gastric gland
48
Identify the structure labeled A.
Palatine tonsil
49
Which of the following cells of the gastric gland secretes HCl?
Parietal cell
50
Which of the following cells of the gastric mucosa secretes hormone basally into underlying blood vessels?
Enteroendocrine cells.
51
Which of the following dental tissues holds the tooth within its bony socket?
Periodontal ligament
52
Numerous gastric glands open directly into this structure?
Gastric pit
53
Which of the following represents an invagination of the surface epithelium into the mucosa?
Gland
54
Where is the pineal gland?
This gland is attached to roof of 3rd ventricle. It secretes melatonin and functions in mood disorders like PMS and seasonal effective disorder.
55
Where are the adrenal (suprarenal) glands?
Synthesizes more than 31 corticosteroids.
56
What is a hormone?
Hormones are chemical messengers secreted into the bloodstream by endocrine (ductless) glands and specialized cells.
57
What is the endocrine system?
Endocrine system consists of these hormone-producing endocrine glands and cells.
58
What are neuroendocrine cells?
These are endocrine cells that communicate with the nervous system.
59
What is corticotropin-releasing hormone (CRH) and what does it act on?
CRH is released from the hypothalamus and acts on the anterior pituitary gland to promote the secretion of adrenocorticotropic hormone (ACTH). ACTH then acts on the adrenal cortex and functions in its growth and release glucocorticoids.
60
What is oxytocin and what does it act on?
Oxytocin is released from the posterior pituitary gland. It functions in labor contractions, milk release, ejaculation, sperm transport in females, parent-offspring bonding. It acts on the uterus, mammary glands, and the brain.
61
What is the anatomy of the adrenal glands?
Adrenal glands sit on top of each kidney. There are two distinct portions; the cortex and medulla.
The adrenal medulla consists of chromaffin cells (modified neurons w/out dendrites or axons) that act as sympathetic ganglion. The medulla secretes catecholamines (epinephrine, NE, and dopamine) in response to stress.
The adrenal cortex has three layers of tissues.
1. zona glomerulosa- outermost. Mineralocorticoids secreted here control electrolyte balance. Aldosterone secreted mainly which acts on kidneys to retain sodium and secrete potassium.
2. zona fasciculata- produce glucocorticoids (mainly cortisol) in response to ACTH
3. zona reticularis- weak androgens and estrogen secreted
62
What is the anatomy of the thymus?
Thymus is located in the mediastinum superior to the heart. This is the location for maturation of white blood cells called T lymphocytes. It also secretes hormones that stimulate the growth of other lymph organs.
63
What hormones have an effect on blood pressure?
Aldosterone
Adrenaline
Cortisol
Erythropoietin
Angiotensinogen
Natriuretic peptides released by heart
64
What glands regressed after childhood and what hormones did they release?
The thymus is large in fetuses and infants and regresses around age 14. The thymus secretes thymopoietin, thymosin, and thymulin.
65
What is the origin and function of insulin?
Insulin is secreted from beta cells in the pancreas. Insulin allows cells to take up glucose from the blood stream and therefore decrease blood sugar.
66
What hormones are secreted by the adrenal cortex?
Medulla secretes catecholamines of epinephrine, NE, and dopamine.
The cortex secretes corticosteroids including aldosterone, cortisol, and weak androgens and some estrogen.
67
What hormones are secreted by the pineal gland?
Pineal gland secretes melatonin in response to dark and light.
68
What hormones are secreted by the parathyroid gland?
The parathyroid gland secretes parathyroid hormone (PTH). PTH increases blood calcium levels.
69
What hormones are secreted by the neurohypophysis?
This is the posterior lobe of the pituitary gland. This portion secretes antidiuretic hormone (ADH) and oxytocin (OT).
70
What are the effects of the different hormones released from the thyroid gland?
Thyroid gland secretes thyroid hormone from thyroid follicles in the form of thyroxine (T4) and triiodothyronine (T3). Thyroid stimulating hormone (TSH) from pituitary allow follicular cells to split thyroid hormones from maker protein, thyroglobulin, and released into the blood. Thyroid hormones increase the activity of mitochondrial enzymes that make ATP and stimulate the activity of sodium-potassium pumps. Also promotes protein synthesis and make pituitary secrete growth hormone.
The parafollicular C cells in between follicular cells secrete calcitonin which lowers blood calcium levels.
71
What are the effects of the hormone glucagon?
Glucagon is secreted by alpha cells in he pancreas. It causes blood sugar to rise but inhibiting cells from taking up glucose from the blood stream.
72
Identify the different portions of the upper respiratory tract.
73
Identify the different portions of the posterior larynx.
74
What are the multiple functions of the respiratory system?
1. Gas exchange between air and blood
2. Speech
3. Smell
4. Control pH of body
5. Aids in BP regulation by assisting in production of angiotensin II
6. Create pressure gradients for lymph and venous flow
7. Defecation
75
What is the order in which air flows through through the respiratory tract?
1. Nose
2. Pharynx
3. Larynx
4. Trachea
5. Lungs
76
What is the boundary between the upper (nose to larynx) and lower (trachea to lungs) respiratory tracts?
The cricoid cartilage connects the larynx to the trachea.
77
What are the functions of central and peripheral chemoreceptors in relation to the respiratory system?
Peripheral chemoreceptors are neurons located in the wall of the aorta and carotid arteries that respond to pH, O2, and CO2 levels in the blood. Central chemoreceptors sense pH in CSF near surface of the medulla.
78
What are the higher brain areas that can influence the respiratory system?
The limbic system, hypothalamus, and cerebral cortex can help control. We exert conscious control over breathing when we hold our breath.
79
How are the medulla and pons related to respiration?
Ventral respiratory and dorsal respiratory nuclei in medulla. Ventral control basic cycle of inspiration and expiration. The dorsal receives input from pontine respiratory group, chemoreceptors, and stretch receptors in the lungs. It modifies output from ventral respiratory group.
The pons contains the pontine respiratory group that modifies breathing rate to adapt to sleep, exercise, vocalization, and emotional responses.
80
What is the role of the diaphragm and where is its location?
The diaphragm is the prime mover of pulmonary ventilation. Contraction pulls muscle down and enlarges thoracic cavity to pull in air.
81
What is the epiglottis and where is it located?
The superior opening of the larynx is covered by a flap called the epiglottis. Its function is to seal off the larynx from food and drink.
82
What is the purpose of the cartilaginous rings in the trachea?
The trachea is supported by 16-20 C shaped rings of hyaline cartilage. These rings keep the trachea from collapsing.
83
What is the common cause of asthma and what is it?
Asthma results from allergic reactions that stimulate bronchoconstriction and airway inflammation.
84
What is the cause of chronic obstructive pulmonary diseases (COPDs) and what are they?
COPDs include chronic bronchitis, emphysema, and asthma. Chronic bronchitis and emphysema are typically due to smoking cigarettes. Chronic bronchitis is associated with repeated infections in lungs and airways congested with sputum. Emphysema leads to the breakdown of alveolar walls and loss of surface area for gas exchange.
85
What is the effect of sympathetic innervation of the lungs?
Increases breathing rate by widening bronchial tubes and narrowing pulmonary blood vessels.
86
What is the effect of parasympathetic innervation of the lungs?
Induces bronchial tubes to narrow and pulmonary blood vessels to expand.
87
What are the different portions of the stomach?
88
Identify the four lobes of the liver.
89
What are the different layers of the digestive tract from lumen to external surface?
1. Mucosa- lines the lumen. Consists of epithelium that overlies lamina propria and muscularis mucosae.
2. Submucosa- loose CT with BVs and nerves
3. Muscularis externa- smooth muscle layer for propulsion and mixing
4. Serosa- areolar tissue topped with simple squamous mesothelium
90
What is the main function of the duodenum?
The duodenum has pleats called circular folds that cause chyme to flow slowly and increase surface area for absorption by mucosa. This is when stomach contents is mixed with bile and pancreatic juices.
91
What is the main function of the appendix?
Acts as a safe house for good bacteria.
92
What is the main function of the stomach?
The stomach stores food, mechanically breaks it down, and begins to chemically digest it.
93
What is the main function of the ileum?
The ileum has patches of lymphatic nodules called Peyer patches.
94
What is the structure of hepatic lobules?
Hepatic lobules are divided into the right, left, quadrate, and caudate lobes. Each hepatic lobe is a small cylinder with a central vein and radiating plate of hepatocytes
95
What is the relationship between hepatocytes and blood in sinusoids?
Hepatic sinusoids are blood-filled spaces lined with loose endothelial cells between the hepatocyte rings. This allows hepatocytes to be in direct contact with plasma so they can absorb nutrients.
96
What is the central vein?
The central vein goes through the hepatic lobules.
97
What is the role of hepatic macrophages?
Hepatic macrophages clean blood.
98
What are the main structural differences between the small and large intestine?
The large intestine is much shorter than the small intestine.
99
What are the names and number of the adult teeth?
There are 32 adult teeth.
Incisors are chisels.
Canines puncture and shred.
Premolars and molars crush and grind.
100
What are the names and numbers of deciduous teeth?
There are 20 deciduous/ baby teeth.
101
What are the different enzymes with saliva and what are their functions?
Saliva is mostly water with other components like amylase and lipase, mucus, lysozymes, immunoglobulin A, and electrolytes.
Amylase- begins to break down starches
Lipase- begin breakdown of fat
Mucus- lubricates food
Lysozyme- kills bacteria
102
Which layer of the tubular gastrointestinal tract wall is responsible for peristalsis?
Muscularis externa
103
Which of the following mineralized tissues covers the root of a tooth?
Cementum
104
Which of the following structures, increasing surface area of the tubular gastrointestinal tract, does not protrude into the lumen?
Gastric gland
105
What is the relationship between the renal pyramid, minor and major calyx, renal pelvis, and ureter?
Kidney divided in to outer renal cortex and inner renal medulla. The medulla is divided into 6-10 renal pyramids each of which has a point facing the sinus called the renal papilla. The renal papilla drips urine into the minor calyx. Two or three minor calyxs converge to form the major calyx and several major calyxs converge in the sinus to form the renal pelvis. The ureter is a continuation of the pelvis that drains urine to the urinary bladder.
106
Identify the sinuses, papilla, major and minor calyxes, renal pelvis, and ureter in the kidneys.
107
Identify the bladder, prostate, internal and external urethral sphincter, prostatic urethra, membranous urethra, spongy urethra, and external urethral orifice in the male urinary tract.
108
What is the function of the urinary system?
Consists of 2 kidneys, 2 ureters, bladder, and urethra.
Functions of the kidneys include
1. filtering blood plasma and excreting waste
2.regulating blood volume and blood pressure
3. Regulate osmolarity
4. regulate electrolyte and acid-base balance
5. secrete erythropoietin for RBC production
6. Synthesize vitamin D for calcium homeostasis
7. clears hormones and drugs
8. support blood glucose levels during starvation
109
Describe the structure and function of the nephron.
The nephron is the functional unit of the kidney. It receives and filters blood plasma and converts urine in 3 stages
1. Glomerular filtration- fluid from bloodstream to nephron at renal corpuscle. Fluid filtered here from blood is called glomerular filtrate.
2. Tubular reabsorption and secretion- In renal tubule, glucose and reabsorbed and returned to blood while toxins are extracted and secreted into tubules to be excreted in urine
3. Water conservation- Most water is reabsorbed in the renal tubule and collecting duct.
Renal corpuscle- filters blood plasma
Renal tubule- converts filtrate into urine
110
Describe the structure and function of the renal corpuscle.
The renal corpuscle consists of the glomerulus and glomerular (Bowman) capsule. Functions in filtering blood plasma.
111
Describe the structure and function of the juxtaglomerular apparatus.
The proximal portion of the distal tubule of the renal tubule contacts afferent and efferent arterioles adjacent to the renal corpuscle. The convergence of these 3 structures forms the juxtaglomerular apparatus that contains 3 special cell types.
Macula densa, juxtaglomerular cells, and mesangial cells.
The juxtaglomerular apparatus functions to maintain blood pressure and to act as a quality control mechanism to ensure proper glomerular flow rate and efficient sodium reabsorption.
112
Identify the 3 layers that must be crossed to pass from the lumen of the glomerular capillary into the filtration space of Bowman's capsule.
The sequence of layers through which the filtration of blood takes place in the nephron is as follows: The endothelium of glomerular blood vessels, basement membrane and the epithelium of Bowman's capsule having cells called podocytes.
113
What are the arterioles of the kidney?
Each kidney supplied by the renal artery. Renal artery branches into a few segmental arteries and further divides into interlobar arteries. These arteries pass between renal pyramids as arcuate arteries. Each arcuate artery gives rise to cortical radiate arteries which extend into the cortex. The cortical radiate arteries give off a lateral branch called the afferent arteriole to each nephron. This arteriole feeds into the glomerulus. An efferent arteriole leaves the glomerulus and then breaks into a network of peritubular capillaries.
114
What is the anatomy, structure and function of the ureters?
The ureter is a muscular tube that passes to the urinary bladder from the renal pelvis. Ureters are around 37cm in length. It has three layers from outside to inside 1) adventitia, 2) muscularis and 3) mucosa
115
How much cardiac output do the kidneys receive?
Kidneys receive about 21% of cardiac output.
116
What is the anatomy of the urinary bladder?
The urinary bladder is a muscular sac on the floor of the pelvic cavity. It has a detrusor muscle which consists of indistinct layers of smooth muscle. The inside of the bladder is lined with transitional epithelium that is 5-6 cells thick.
117
What are the 3 regions of the male urethra?
1. Prostatic urethra- begins at bladder and passes through prostate gland
2. Membraneous urethra- short thin walled portion that passes through the muscular pelvic floor
3. spongy urethra- passes through the penis to the external urethral orifice.
118
What is the composition of urine while being excreted?
Human urine is 95% water, the rest is urea, creatinine, uric acid, chloride, sodium, potassium, sulphate, ammonium, phosphate, and more.
119
Identify structure "F"
Renal papilla
120
Which of the following is NOT a part of the nephron?
Collecting duct
121
Which labeled structure on the diagram represents the efferent arteriole?
B
122
What is the specific function of the peritubular capillaries?
Reabsorption
123
Identify the structure labeled C.
Filtration (glomerular) membrane
124
Which specific cell type becomes modified into a juxtaglomerular (JG) cell?
Smooth muscle of arteriole wall
125
Identify B
Macula Densa
126
Which of the labeled structures represents the membranous urethra?
C
127
In what region of the renal tubule is the majority of the water that was lost in the glomerulus reabsorbed?
Proximal convoluted tubule
128
Where is the lowest point a kidney stone is likely to get stuck?
Where ureter pierces the bladder.
129
What is sexual reproduction?
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete with a single set of chromosomes combines with another gamete to produce a zygote that develops into an organism composed of cells with two sets of chromosomes.
130
What are the female primary and secondary sex organs and characteristics?
The primary is the ovaries.
Secondary is uterine tubes, uterus, and vagina
Secondary sex characteristics include pubic and axillary hair as well as the distribution of fat on breasts and hips.
131
What is the anatomy of the scrotum?
The scrotum is the pouch that carries the testes. The function of the scrotum is to regulate the temperature of the testes. It has a cremaster muscle that contracts and draws the scrotum up into the body when it is cold and relaxes when warm. The dartos muscle is a layer of smooth muscle that contracts when it is cold and makes the testes wrinkled and taut. There is also a network of veins called the pampiniform plexus which surrounds that testicular artery in the spermatic cord and acts as a heat exchanger.
132
What are the male primary and secondary sex organs and characteristics?
The primary is testes.
Secondary is epididymis, vas deferens, and penis.
The secondary sex characteristics for males include pubic and axillary hair as well as a deeper voice, facial hair, and increased muscle mass.
133
What is the anatomy of the testes?
The testes are endocrine and exocrine glands that produce sex hormones and sperm. The testes are enclosed in a sac called the tunica vaginalis which is an extension of the peritoneum. The surface of the testes is covered by a white fibrous capsule called the tunica albuginea. Septa from the tunica albuginea divides the testes into lobules. Each lobule contained a seminiferous tubule. In the germinal epithelium that lines the seminiferous tubules, there are layers of germ cells and sustentacular cells that provide nutrients and growth factors for the germ cells. In between seminiferous tubules, there are interstitial Leydig cells that produce testosterone.
134
What is the anatomy spermatic duct?
The efferent ductules carry sperm from testis to epididymis. The epididymis contains a coiled duct that is around 6 meters long. Sperm travel through the epididymis and are stored there till ejaculation. The epididymis then straightens out and becomes the ductus (vas) deferens which passes from the scrotum through the inguinal canal and into the pelvic cavity. It travels behind the bladder and terminates to join with the duct of the seminal vesicle. The last duct is the ejaculatory duct which is formed where the ductus deferens meets the seminal vesicle. The ejaculatory duct passes through the prostate and empties into the urethra.
135
What is the anatomy of the penis?
3 cylindrical bodies filled up with blood during arousal. The corpus spongiosum is on the ventral side and the corpus cavernosum is on either side of the dorsal penis. It has a glans which is an expanded head and skin continues over the glans called prepuce or foreskin.
136
What are the stages of spermatogenesis?
Spermatogenesis is the process of sperm production. It takes place in the seminiferous tubules where a large germ cell is transformed into a small motile cell with half the usual number of chromosomes. Sperm cells are produced through the process of meiosis (cell division that generates gametes).
1. In the male embryo, primordial germ cells colonize the embryonic testes. These stem cells are called spermatogonia and have 46 chromosomes (normal number). These spermatogonia remain dormant until puberty in which testosterone promotes spermatogenesis.
2. Once spermatogenesis begins, the spermatogonia divide via mitosis. Daughter cells from mitosis either become stem cells called type A spermatogonia (supply of stem cells) or type B spermatogonia which will become mature sperm.
3. Type B spermatogonia becomes primary spermatocyte.
4. Primary spermatocyte undergoes meiosis 1 where the chromosome number is reduced by half and produces daughter cells called secondary spermatocytes.
5. The secondary spermatocytes undergo meiosis II where the chromosomes are reduced from double-stranded to single-stranded. This results in 4 daughter cells called spermatids that each have 23 chromosomes.
6. Spermatids will then undergo spermiogenesis in which they lose cytoplasm and grow a tail and become spermatozoon.
It takes around 74 days for a spermatogonia to become a mature spermatozoon.
137
What is a sperm cell?
A sperm cell is a spermatozoon. It has a head and a tail. The head contains a nucleus and lysosome that penetrates the egg. The tail contains a lot of mitochondria in the midpiece to move the tail.
138
What is the composition of sperm?
Semen is 10% sperm, 30% prostatic fluid, and 60% seminal vesicle fluid.
Semen contains small amounts of more than thirty elements, including fructose, ascorbic acid, cholesterol, creatine, citric acid, lactic acid, nitrogen, vitamin B12, and various salts and enzymes.
139
What is the structure of an ovary?
The ovaries produce eggs cells and hormones. Each ovary is about 3 cm long and lies in the dorsal pelvic cavity. The ovaries are covered by a tunica albuginea. Inside, the medulla of the ovary consists of fibrous CT with arteries and veins while the cortex is the site of the ovarian follicles that contain the ovum and follicular cells.
140
What are the stages of oogenesis and how do these stages relate to changes in histology in the ovarian follicles?
Oogenesis is the production of female gametes. During embryonic development, germ cells arise from the yolk sac and migrate to gondal regions where they differentiate into oogonia. Oogonia multiply until 5th month of embryonic development. Before birth, some oogonia undergo meiosis 1 becoming primary oocytes. By the time a fetus is born, there are around 2 million primary oocytes and the number is around 400,000 by puberty. During puberty, around 25 oocytes begin to develop each month and typically only 1 reaches maturity and ovulates.
1. Primary oocyte initially enclosed in a primordial follicle (single layer of squamous follicular cells around the ovum). At the beginning of the cycle, FSH stimulates several primordial follicles to develop into primary follicles. During this, the follicular cells thicken to cuboidal epithelium and then become stratified granulosa cells. The ovarian stroma around the follicle condenses into a fibrous capsule called the theca folliculi. The theca and granulosa cells produce estrogens.
2. At this point, when the theca and granulosa cells are present, the follicle is a secondary follicle. By day 10 of the ovarian cycle, all but one follicle degenerates.
3. Develops into tertiary and then mature Graafian follicles. The mature Graafian follicle contains an oocyte that will undergo phase I of meiosis and divide into a secondary oocyte and small first polar body so it can retain as much cytoplasm as possible.
4. The secondary oocyte begins meiosis II but the division is arrested until after ovulation. If fertilized, the egg will complete meiosis II. Ovulation occurs on day 14 of the ovarian cycle. During this, the mature follicle ruptures, and the fluid carrying the oocyte and surrounding layers ooze out.
5. After ovulation, the follicle collapses and is transformed into a corpus leutum. This structure produces progesterone and readies the uterus for pregnancy. If pregnancy does not occur, the progesterone levels drop and bleeding occurs. If the egg is fertilized, the corpus leutum produces progesterone for the first 3 months of pregnancy.
6.
141
What is the structure of a nonlactating breast?
Nonlactating breasts consist mostly of adipose and collagenous tissue. Suspensory ligaments attach to the breast to the dermis of the overlying skin and fascia of the pectoralis muscle.
142
What is the structure of a lactating mammary gland?
During pregnancy, the mammary gland develops 15-20 lobes arranged around the nipple. Each lobe is drained to a lactiferous duct which dilates to a lactiferous sinus opening on the nipple. The lactiferous ducts branch to secretory acini organized like grapes within each lobe. Each acinus contains pyramidal cells and myoepithelial cells. Stimulation of the nipple during nursing leads to the release of oxytocin which targets myoepithelial cells to contract and squeeze milk into lactiferous ducts.
143
What is the anatomy of the uterus and how does it connect to the ovary?
The uterus is a muscular chamber superior to the vagina for nourishment, protection, and delivery of the fetus. It has 3 layers: the outer layer called perimetrium, the thick muscle layer called myometrium, and the inner mucosa called endometrium. The endometrium has two layers, a thick superficial stratum functionalis (shed during period) and a thinner inner layer called stratum basalis which is retained between cycles. The uterine tubes/ fallopian tubes connect the uterus to the ovaries.
144
What is the definition of ovulation?
Ovulation is when the mature Graafian follicle ruptures.
145
How many primary oocytes does a female have by the onset of puberty?
There are around 400,000 primary oocytes in females by the onset of puberty.
146
What is the function of myoepithelial cells?
Myoepithelial cells are contained within the lobules of the lobes. Oxytocin acts on these cells to contract and squeeze milk into lactiferous ducts.
147
What is the function of the tunica albuginea?
In males- the tunica albuginea covers the testes and is a shiny, white, fibrous capsule. It divides the testes into lobules.
In females- the tunica albuginea covers the ovaries.
148
What is the function of the epididymis?
The mature sperm travels through here and is stored and matures in the epididymis.
149
What is the anatomy of the prostate gland?
The prostate gland surrounds the urethra and ejaculatory ducts immediately inferior to the bladder. Its secretions enter the urethra and constitute 30% of semen.
150
What is the erectile tissue in females?
Deep to the labia majora is the subcutaneous erectile tissue called the vestibular bulbs. These bracket the vagina and become congested with blood during sexual excitement.
151
Which of the following connects the testes with the ductus (vas) deferens?
Efferent ductule
152
What is the letter H?
Epididymis
153
What is letter C in this posterior view of the male reproductive system?
Seminal vesicle
154
What is the letter D on the diagram?
Rete testis
155
Fertilization of the egg normally occurs within which region of the female reproductive system?
Uterine tube
156
Identify the letter F in the diagram.
Corpus luteum
157
Identify region C.
Infundibulum
158
Identify the letter B.
Suspensory ligaments
159
Which feature concerning the vagina is FALSE?
Numerous mucous glands open into the vaginal canal for lubrication during intercourse.
