Module 6.2 Male Reproductive System and Special Sense Flashcards
(309 cards)
1
Q
Consists of:
- Two gonads, the testes, which produce male germ cells and male sex hormones
- A copulatory organ, the penis
- A set of tubes and tubules which transmit the male germ cells from the testes to the penis
- Accessory glands – seminal vesicle, prostate gland and bulbourethral glands, which provide a fluid medium for carrying the male germ cells
A
Male Reproductive System
2
Q
Gonads – primary sex organs
A
Testes in males
Ovaries in females
3
Q
Gonads produce gametes (sex cells) and secrete hormones
A
Sperm – male gametes
Ova (eggs) – female gametes
4
Q
(Development of the Gonads)
These appear as a pair of longitudinal ridges which are formed by proliferation of the coelomic epithelium and condensation of the underlying mesenchyme called the __ during the 5th week of development.
A
genital ridge or gonadal ridge
5
Q
(Development of the Gonads)
In the 6th week of development, the primordial germ cells derived from the yolk sac __, invade the genital ridge.
A
endoderm
6
Q
(Development of the Gonads)
During the arrival of the primordial germ cells, the coelomic epithelium of the genital ridge proliferates and epithelial cells penetrate the underlying mesenchyme forming irregularly shaped cords, the __.
A
primitive sex cords
7
Q
(Development of the Gonads)
Before the 7th week of development, the gonads of the two sexes are identical in appearance and are called __.
A
indifferent gonads
8
Q
(Sex Determination)
__ is determined by the testis determining factor / TDF on the Y chromosome.
A
Gonadal sex
9
Q
(Development of the Testis)
If the embryo is genetically male, the primitive sex cords continue to proliferate to form the testes or medullary cords. Later, this gives rise to the __.
A
seminiferous tubules and the rete testis
10
Q
(Development of the Testis)
Then the testis cords will lose its contact with surface epithelium and will be covered with a dense layer of connective tissue, the __.
A
tunica albuginea
11
Q
(Development of the Testis)
The testis cords are composed of __
A
primitive germ cells and Sertoli cells
12
Q
(Development of the Testis)
The __ are derived from the mesenchyme of the gonadal ridge located between the testis cords.
A
Leydig cell
13
Q
(Development of the Testis)
From the 8th weeks of development, the Leydig cells secrete testosterone, which induces masculine differentiation of the mesonephric ducts and external genitalia. While the Sertoli cells secrete __ which inhibits development of the paramesonephric ducts.
A
Mullerian inhibiting substance
14
Q
(Development of the Testis)
Due to the rapid growth of the dorsal wall of the embryo, the testes gradually descend behind the abdominal position until the __.
A
7th month
15
Q
(Development of the Testis)
From the 7th month until birth, there is progressive shortening of gubarnaculum testis. At birth, the testis is inside the __.
A
scrotal sac
16
Q
Coverings of the testes
A
Tunica albuginea – capsule that surrounds each testis
Septa – extensions of the capsule that extend into the testis and divide it into lobules
17
Q
- Tightly coiled structures
- Function as sperm-forming factories
- Empty sperm into the rete testis
A
seminiferous tubules
18
Q
- Each lobule contains one to four seminiferous tubules
- Sperm travels through the rete testis to the epididymis
- Interstitial cells produce androgens such as testosterone
- are compound tubular glands lodged in the scrotum.
A
Testes
19
Q
The __ is a pendulous bag of skin with a thin wall, an incomplete layer of smooth muscle (Dartos muscle) and some subcutaneous tissue. It has a considerable surface area and it is believed that this permits its contents to be maintained at a temperature slightly below that of the body. This lower temperature is important for spermatogenesis or the production of sperm cells.
A
scrotum
20
Q
- develop retroperitoneally within the abdominal cavity.
- They descend into the scrotum, where the cooler temperature are more hospitable for spermatogenesis
A
Testes
21
Q
Testes
A
- During the descent of the testis, it carries an evagination of the peritoneal cavity into the scrotum.
- Usually, the connection between this processus vaginalis and the peritoneal cavity proper in obliterated later in life, leaving a tunica vaginalis.
- The anterior and lateral aspects of the testes are coated with a mesothelium that once was continuous with the mesothelium lining the peritoneal cavity.
22
Q
The testes is surrounded by three layers of testicular capsule:
A
- an outer tunica vaginalis
- middle tunica albuginea
- inner tunica vasculosa.
23
Q
The __ contains a network of blood vessels.
A
tunica vasculosa
24
Q
- is a thick, fibrous connective tissue capsule that lies beneath the mesothelium.
- It penetrates deeply into the posterior aspect of the testes, forming the mediastinum testis
A
tunica albuginea
25
- is located in the mediastinum testis.
| - It is through here that ducts, blood vessels, nerves, and lymphatic vessels enter and leave.
hilus of the testis
26
Along the posterior border of each testis, the capsule becomes greatly thickened and is known as the __.
mediastinum testis
27
The __ divide the testis into numerous pyramidal compartments called testicular lobules.
fibrous partitions (septuli testis)
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(Testes)
Each lobule contains one to four highly convoluted seminiferous tubules supported by fibrous connective tissue containing the __, which are large cells with an endocrine function
interstitial cells of Leydig
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(Testes)
| At the apex of the lobule, each lobule becomes a straight lobule called the __.
tubuli recti
30
(Testes)
The tubuli recti in turn anastomose and form a network of tubules called the __ which is found in the mediastinum testis.
rete testis
31
(Testes)
Arising from the rete testis are about 2 – 15 convoluted tubules called the __, which passes to the head of the epididymis.
ductuli efferentes
32
(Testes)
The highly tortuous __ forms the body and tail of the epididymis.
ductus epididymis
33
From the tail of the epididymis emerges the ductus deferens (vas deferens), one of the components of the spermatic cord. It ascends into the abdominal cavity to terminate behind the urinary bladder. Its’ terminal end forms a fusiform dilation called ampulla of the vas deferens. The terminal end of the ampulla fuses with the excretory duct of the seminal vesicle to form the __.
ejaculatory duct
34
The ejaculatory duct pierces the prostate gland to open into the prostatic urethra to the side of the __.
prostatic utricle
35
The wall of the __ is made up of a seminiferous epithelium, thin basement membrane and an outer capsule of fibro-elastic connective tissue.
seminiferous tubule
36
(SEMINIFEROUS TUBULES)
The lining epithelium is a complex stratified epithelium composed of two distinct categories:
- Supporting cells
| - Spermatogenic cells
37
- The interstices between seminiferous tubules are filled with small vessels and lymphatics.
- Connective tissue fibroblasts and, possibly, macrophages and lymphocytes occur here.
- Most importantly, the Leydig cells, specialized for the secretion of the male sex hormone, testorterone, are found here.
Interstitial Cells
38
- Also known as sustentacular or Sertoli cells.
- These cells have a supportive function in relation to the spermatogenic cells. They are tall, slender, elongated with irregular outline, rest on the basement membrane and extend through the full thickness of the epithelium. The cytoplasm contains numerous organelles with a well developed SER at the base of the cell, probably significant in the secretory function of the cell.
SUPPORTING CELLS
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- Electron microscopy reveals pairs of apposed membranes (tight junctions) between adjacent Sertoli cells and between germ cells. This plays an important role in the formation of a blood-testis permeability barrier which isolates and protects the differentiating spermatogenic cells. It represents a barrier between the lumen of the semineferous tubule and the extratubular compartment.
- The spermatogonia that rest on the basement membrane have a good supply of nutrients, but the cells nearer the lumen of the tubule have no direct access to tisssue fluid because of the intervening Sertoli cells.
SUPPORTING CELLS
40
Dividing spermatocytes, spermatids and spermatozoa are nourished by the __.
Sertoli cells
41
Functions of the Sertoli Cells
1. Provide mechanical support and protection to the developing germ cells.
2. Provide nutrition for the developing germ cells.
3. Play an active role in the release of spermatozoa.
4. Phagocytosis of cellular fragments.
5. Formation of blood-testis permeability barrier.
42
The __, from the bulk of the epithelium, give rise to mature spermatozoa by spermatogenesis. Spermatogenesis refers to the entire sequence of events wherein spermatogonia are transformed into spermatozoa.
spermatogenic cells
43
- Production of sperm cells
- Begins at puberty and continues throughout life
- Occurs in the seminiferous tubules
Spermatogenesis
44
Processes of Spermatogenesis
- Spermatogonia (stem cells) undergo rapid mitosis to produce more stem cells before puberty
- Follicle stimulating hormone (FSH) modifies spermatogonia division
* One cell produced is a stem cell
* The other cell produced becomes a primary spermatocyte
- Primary spermatocytes undergo meiosis
- Haploid spermatids are produced
- Spermatogenesis takes 64 to 72 days
45
Divisions of Spermatogenesis
1. Spermatocytogenesis - Mitosis of spermatogonia to become spermatocytes
2. Meiosis - Maturation division of spermatocytes which reduce the chromosome number by half and produces spermatids
3. Spermiogenesis - Spermatids are transformed directly into spermatozoa
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- Located beneath the basement membrane of the seminiferous tubules.
- Contain a round, dark staining nucleus.
Spermatogonia
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Spermatogonia: 2 Types
1. Type A spermatogonia
| 2. Type B spermatogonia
48
- Contain an oval nucleus with fine chromatin granules.
- Its cytoplasm is homogenous and pale staining.
- The nucleolus lies close to the nuclear membrane.
- These cells undergo a series of mitotic divisions that give rise to other Type A spermatogonia, while other differentiate into Type B spermatogonia.
Type A Spermatogonia
49
- Contain a spherical nucleus containing chromatin masses which are heavily stained, large and of varying sizes.
- The single nucleolus is centrally located and the cytoplasm is somewhat dark staining.
- These cells give rise to primary spermatocytes.
Type B Spermatogonia
50
- The biggest of the spermatogenic cells with plenty of mitotic figures in their nuclei.
- These are seen in various stages of prophase because the stage of mitotic prophase is extremely prolonged.
- These undergo the first meiotic division and become transformed into secondary spermatocytes.
Primary Spermatocytes
51
- These are spherical or polygonal in shape with a small, dark staining nucleus with finely granular chromatin.
- These cells undergo spermiogenesis and become transformed into mature germ cells.
- Only few are seen in section because they transform rapidly into spermatozoa.
Secondary Spermatocytes
52
- Spermatozoa begin to proliferate rapidly at puberty and, by division, produce primary spermatocytes
- Primary spermatocytes enter meiosis I, the first meiotic division, and produce secondary spermatocytes
- In meiosis II, secondary spermatocytes divide and form haploid spermatids
Spermatogenesis
53
- Mature sperm cells, actively motile, swim freely.
- Consists of a head, middle piece, body and a tail.
- They are quiescent in the seminiferous tubules and ducts of the testis and become active by the secretion of the accessory glands.
- Production begins at puberty, continues throughout life but diminishes with age.
Spermatozoa
54
- Refers to the process of converting spermatids into spermatozoa.
Spermiogenesis
55
There are three events during spermiogenesis
- Acrosome formation
- Flagellum and midpiece formation
- Streamlining of spermatozoa
56
- Golgi membranes coalesce to form an acrosomal granule
| - The acrosomal granule flattens around the nucleus to form an acrosomal cap
Acrosome Formation
57
- Centrioles migrate to the spermatid pole, opposite the acrosome
- One centriole forms a flagellum
- Mitochondria group around the base of the flagellum to form the midpiece
Flagellum and Midpiece Formation
58
- Nuclear condensation results in a pointed streamlined nucleus
- Excess cytoplasm is shed as a residual body which is engulfed by the Sertoli cells
Streamlining of Spermatozoa
59
Structure of a Mature Sperm Cell
- The only human flagellated cell
| - DNA is found in the head
60
- These are clusters of epitheloid cells which are largely cells with pale staining spherical to oval nuclei.
- They are usually acidophilic and found scattered in the stroma between the sminiferous tubules.
- These cells secrete testosterone.
Interstitial Cells of Leydig
61
- are about 20 micrometer in diameter and usually are found in close association with small blood vessels; this is not surprising since they are responsible for the secretion of testosterone into the blood
- has an acidophilic cytoplasm and a prominent nucleus with a nucleolus, when seen in the light microscope
- With the electron microscope they exhibit an abundance of smooth endoplasmic reticulum and a prominent Golgi apparatus
- contain cholesterol which they use to synthesize testosterone on membranes of the smooth endoplasmic reticula
Leydig cells
62
The production of androgen by Leydig cells is under the control of the __
pituitary gland
63
Cells of the pars distalis secrete __, which sometimes is called interstitial cell-stimulating hormone (ICSH). It is a gonadotrophic hormones, stimulates the Leydig cells to release testosterone
luteinizing hormone (LH)
64
High levels of testosterone then feed back on the hypothalamus and inhibit the production of __ in a classic negative feedback loop
luteinizing hormone relealsing hormone (LH-RH)
65
Following hypophysectomy, there is a complete degeneration of the __, no testosterone production, and a cessation of spermatogenesis
interstitial cells of Leydig
66
Following castration, testosterone levels fall rapidly and the gonadotrops are under chronic hypothalamic stimulation by LH-RH, resulting in the appearance of __ in the pars distalis
castration cells
67
- The most important hormone of the testes
| - Produced in interstitial cells
Testosterone
68
Functions of testosterone
- Stimulates reproductive organ development
- Underlies sex drive
- Causes secondary sex characteristics
* Deepening of voice
* Increased hair growth
* Enlargement of skeletal muscles
* Thickening of bones
69
Testicular Drainage Ducts
- Tubuli recti
- Rete testis
- Efferent ductules
- Epididymis
- Ductus deferens
- Ejaculatory ducts
70
- Straight portions of loops of seminiferous tubules
- Lined by Sertoli cells
- Join the rete testis
Tubuli Recti
71
- Conveys gametes from the tubuli recti to the efferent ductules
- Lined by cuboidal ciliated cells
Rete Testis
72
- Continuous with the rete testis
- Empty into the epididymis
- Surrounded by smooth muscle cells
- The simple epithelium is lined by alternating groups of tall columnar ciliated cells and low columnar non-ciliated cells.
- Thus, the lumen is irregular and described as having a “festooned appearance”.
- The cilia help in transporting spermatozoa to the epididymis.
Efferent Ductules
73
- Lined by a tall pseudostratified epithelium
- The tall cells have long, apical nonmotile stereocilia.
- These are secretory cells also, producing certain constituents of ejaculate
- Short cells rest on a basement membrane and probably serve as a stem cell population to replace effete tall cells
Epididymis
74
- probably modifies the contents of ejaculate by removal and addition of various materials (i.e., stereocilia absorb and tall columnar cells secrete)
- Spermatozoa from the head of the epididymis are poorly motile and incapable of fertilizing ova in vitro
- Whereas spermatozoa from the tail of the epididymis are highly motile and capable of fertilizing ova in vitro. This change in the spermatozoa is called capacitation
Epididymis
75
- Comma-shaped, tightly coiled tube
- Found on the superior part of the testis and along the posterior lateral side
- Functions to mature and store sperm cells (at least 20 days)
- Expels sperm with the contraction of muscles in the epididymis walls to the vas deferens
Epididymis
76
- Highly convoluted tubule which functions as storage organ of the spermatozoa.
- It is also where the sperm cells acquire the properties of motility and fertilizability.
- The lining epithelium is pseudostratified columnar with stereocilia.
- Scattered among the columnar cells at various levels in the epithelium are small cells with pale staining cytoplasm and dark heterochromic nuclei. These are termed “halo cells” which are intraepithelial lymphocyte
DUCTULI EPIDIDYMIS
77
Gross Anatomy of Ductus Deferens
- The tubular ductus deferens (vas deferens) recieves spermatozoa and secretions from the epididymis and conveys them to the prostate.
- Near the epididymis the ductus deferens is relatively coiled, but close to the prostate it is rather straight
78
Gross Anatomy of Ductus Deferens (2)
- Proximal to the prostate gland, the ductus deferens is dilated into an ampullary portion, where it is joined by a sac-like diverticulum called the seminal vesicle
- After they join, the ductus deferens and seminal vesicle enter the prostate as an ajaculatory duct
79
- is lined by a pseudostratified epithelium that is supported by testosterone secretion from Leydig cells
- The tall columnar cells of this epithelium bear long, nonmotile microvilli called stereocilia
- has a mucosa, a muscularis and an adventitia
ductus deferens
80
Histology of Ductus Deferens
- The mucosa is thrown into gentle undulations
- It has a thin lamina propria
- The muscularis is composed of three concentrically arranged layers – an inner and outer layer arranged longitudinally and a middle circular layer
- The adventitia contains small amounts of connective tissue, blood vessels and nerves
- It lacks a mesothelium
- In the ampullary portion of the ductus deferens, the mucosal folds are considerably higher and more complicated
- The ampulla, like the seminal vesicle, looks like a gland
81
- Carries sperm from the epididymis to the ejaculatory duct
- Passes through the inguinal canal and over the bladder
- Moves sperm by peristalsis
- Spermatic cord – ductus deferens, blood vessels, and nerves in a connective tissue sheath
- Ends in the ejaculatory duct which unites with the urethra
Ductus Deferens (Vas Deferens)
82
– cutting of the ductus deferens at the level of the testes to prevent transportation of sperm
Vasectomy
83
- Also known as the vas deferens.
- The mucosa is lined by pseudostratified columnar epithelium. Together with the lamina propria, it is thrown into several longitudinal folds so that the lumen is narrow and irregular in outline.
- The muscularis layer is the thickest layer and gives the vas deferens a firm consistency. It is made up of inner longitudinal, middle circular and outer longitudinal layers. The muscles propel the seminal fluid during ejaculation.
DUCTULI DEFERENS
84
- The adventitia is loose fibroelastic connective tissue and blends with the tissues of the spermatic cord.
- The spermatic cord consists of the vas deferens and its accompanying artery, pampiniform plexus of veins and nerves. The cord is enclosed by the cremaster muscle.
- The ampulla of the vas deferens has a wider lumen and the mucosa is much more folde
DUCTULI DEFERENS
85
The primitive genital ducts consist of 2 parts namely:
- Mesonephric duct (Wolffian duct)
| - Paramesonephric duct (Mullerian duct)
86
(Development of the Male Genital Ducts)
In males, the __ persists as the ductal system of the testis. The paramesonephric duct regresses.
mesonephric duct
87
(Development of the Male Genital Ducts)
From the cranial to the caudal position, the __ gives rise to the epididymis, ductus deferens and ejaculatory ducts. The ductus deferens gives rise to a saccular pouch which forms the seminal vesicle.
mesonephric duct
88
- Formed by the union of the ampulla of the vas deferens and excretory ducts of the seminal vesicle.
- Opens into the prostatic utricle.
- Lined by pseudostratified columnar epithelium.
- These ducts penetrate the prostate and join the prostatic urethra in a single midline thickening of the mucosa known as the colliculus seminalis
EJACULATORY DUCTS
89
ACCESSORY GLANDS
- Seminal vesicle
- Prostate gland
- Bulbo-urethral glands
- Penis
90
- A pair of convoluted sacs behind the urinary bladder which secretes and stores a yellow, viscous alkaline fluid rich in fructose that nourishes the spermatogenic cells and forms part of the seminal fluid.
SEMINAL VESICLE
91
- Located at the base of the bladder
- Produces a thick, yellowish secretion (60% of semen)
* Fructose (sugar)
* Vitamin C
* Prostaglandins
* Other substances that nourish and activate sperm
SEMINAL VESICLE
92
Like the ductus deferens, each seminal vesicle is lined by a __ that is supported by testosterone secretion from Leydig cells
pseudostratified epithelium
93
SEMINAL VESICLE
- With the electron microscope, the tall columnar secretory cells of the epithelium show a basal rough endoplasmic reticulum, a prominent Golgi apparatus and secretory granules
- The smooth muscle layers in the seminal vesicle are not neatly arranged; rather, they merge indistinctly into the smooth muscle surrounding the ejaculatory duct and into the prostate
94
Functions of the Seminal Vesicle
- Produce a substantial volume of the ejaculate
- Secretion of the seminal vesicles is viscous and yellowish
- Secretion contains materials that are probably nutrtitive for the spermatozoa
- Secretion contains prostaglandin
95
- The mucosa forms a complicated series of primary folds which branch into secondary and tertiary folds.
- The lining epithelium is pseudostratified columnar epithelium.
- The tunica muscularis is composed of smooth muscles in two layers: inner circular and outer longitudinal.
- The tunica adventitia is dense collagenous tissue with blood vessels, lymph vessels and nerves.
SEMINAL VESICLE
96
- Encircles the upper part of the urethra
- Secretes a milky fluid
* Helps to activate sperm
* Enters the urethra through several small ducts
Prostate Gland
97
- This is a compound tubulo-alveolar gland located below the urinary bladder and surrounds the first part of the urethra.
- It is surrounded by a fibroelastic capsule that also contains smooth muscle. The capsule gives off fibromuscular septa which divides the gland into lobes and lobules.
- The alveoli are lined by pseudostratified columnar epithelium.
- The cells secrete a thin, somewhat milky fluid. It is the main source of acid phosphatase, citric acid and amylase of semen.
PROSTATE GLAND
98
- is compact mass of smooth muscle and elaborately branched glands.
- A more detailed inspection reveals two types of glands:
* Periurethral mucosal glands
* Main secretory glands of the prostate proper
Prostate Gland
99
- Although small, these glands commonly undergo hyperplastic growth with advancing age.
- As a result, benign prostatic hyperplasia occurs, constricting the prostatic urethra
- BPH can be corrected surgically by a transurethral resection
periurethral mucosal glands
100
- The epithelium of this gland is columnar or pseudostratified at the gland’s main segment but grades into transitional epithelium where the gland empties into the prostatic urethra
- When viewed in the electron microscope the epithelial cells appear typical for protein-secreting cells
main secretory glands of the prostate proper
101
Functions of the Prostate Gland
- The prostate produces the majority of the volume of seminal fluid
- The secretions of the prostate are rich in proteolytic enzymes (especially fibrinolysin), which probably function to liquify the semen after it is deposited in the vagina
- Presumably, this liquefaction allows spermatozoa to free themselves from the viscous ejaculate and begin traveling through the cervix and uterus to the oviducts
- These secretions solidify sometimes in the gland and can be seen, especially in older men, as prostatic concretions
102
(Prostate Gland)
The lumen of the alveoli may contain spherical concentrically lamellated bodies called __.
prostatic concretions or corpora amylacea
103
- Pea-sized gland inferior to the prostate
- Produces a thick, clear mucus
* Cleanses the urethra of acidic urine
* Serves as a lubricant during sexual intercourse
* Secreted into the penile urethra
Bulbourethral Glands
104
- Also known as Cowper’s glands.
- Pair of small, compound, tubulo-alveolar glands embedded in the urogenital diaphragm.
- The glands secrete an alkaline fluid and mucous which probably serves as a lubricant.
- Their ducts enter the membranous urethra.
- Its excretory ducts are lined by pseudostratified epithelium.
- In the enlarged alveoli, the cells are flattened; but if the alveoli are empty, the cells are cuboidal or columnar.
Bulbourethral Glands
105
(Development of the Male External Genitalia)
Mesenchymal cells migrate around the cloacal membrane to form a pair of slightly elevated folds, the cloacal folds. These folds unite to form the __.
genital tubercle
106
(Development of the Male External Genitalia)
Under the influence of androgens secreted by the fetal testis, there is rapid elongation of the genital tubercle which is now called the phallus. As it elongates, it pulls with it the urethral fold forward to form the urethral groove, the floor of which is known as the __.
urethral plate
107
(Development of the Male External Genitalia)
At the end of the 3rd month, the two urethral folds close over the urethral plate forming the penile urethra. The most distal portion of the urethra is formed during the 4th month when ectodermal cells from the tip of the glans penetrate inwards and forms a solid epithelial cord. Later, this cord obtains a lumen forming the definitive __.
external urethral meatus
108
(Development of the Male External Genitalia)
The genital swellings in male known as scrotal swellings form the __.
scrotum
109
- Extends from the base of the urinary bladder to the tip of the penis
- Carries both urine and sperm
- Sperm enters from the ejaculatory duct
Urethra
110
Regions of the urethra
Prostatic urethra –surrounded by prostate
Membranous urethra – from prostatic urethra to penis
Spongy (penile) urethra – runs the length of the penis
111
- Divided sac of skin outside the abdomen
| - Maintains testes at 3°C lower than normal body temperature to protect sperm viability
Scrotum
112
- Internally there are three areas of spongy erectile tissue around the penile urethra
External Genitalia
113
- Delivers sperm into the female reproductive tract
- Regions of the penis
* Shaft
* Glans penis (enlarged tip)
* Prepuce (foreskin)
Penis
114
- Folded cuff of skin around proximal end
| - Often removed by circumcision
Prepuce (foreskin)
115
Anatomy of the Penis
- The penis has paired dorsal corpora cavernosa and a single midline corpus spongiosum, which contains the uretha
- These three bodies are bound together by a tough fibrous connective tissue capsule known as the tunica albuginea, and they are covered by a thin layer of skin that has an unusually rich sensory innervation
- Functions both as a sex organ and as an organ for urine excretion
116
Anatomy of the Penis (2)
- The cavernous bodies of the penis consist of erectile tissue that grows and becomes rigid when filled with blood
- Helical arteries that drain into a venous plexus bring the cavernous bodies a rich supply of blood
117
Penis in Sexual Function
- During erection, the blood flow into the venous sinuses is greater than the blood flow out, causing the sinuses to fill with blood and causing tumescence of the organ
- Following a sexual encounter, the blood flow to these sinuses slows and the penis becomes flaccid again
118
The __ consists of three cylindrical masses of erectile tissue; a pair of corpora cavernosa and an unpaired corpus spongiosum. Each body is surrounded by tunica albuginea. In the corpora cavernosa, the spaces are lined by endothelium which is continuous with the endothelium of the arteries and veins. Partitions called trabulae, consisting of dense fibrous tissue.
penis
119
- Mixture of sperm and accessory gland secretions
- Advantages of accessory gland secretions
* Fructose provides energy for sperm cells
* Alkalinity of semen helps neutralize the acidic environment of vagina
* Semen inhibits bacterial multiplication
* Elements of semen enhance sperm motility
Semen
120
- Undescended testis
- Unilateral or bilateral
- Due to abnormal production of androgen or failure of the gubernaculum testis to shorten
Cryptochidism
121
- Results from incomplete fusion of the urethral folds
| - Abnormal openings of urethra along the ventral aspect of the penis
Hypospadias
122
- The external urethral meatus is found on the dorsal aspect of the penis
Epispadias
123
- With a karyotype of 47 XXY
| - Characterized by infertility, gynecomastia and impaired sexual maturation
Klinefelter’s syndrome
124
- Have a 44 + XY chromosome but have the external appearance of normal females
Testicular Feminization syndrome
125
- Genotype sex is masked by a phenotype appearance
- Male pseudohermaphrodites (When patient has a testes)
- Female pseudohermaphrodite (When patient has an ovary)
Pseudohermaphrodites
126
- Applied to group of disease that can be spread by sexual contact
Sexually transmitted disease
127
- Is the second leading cause of death from cancer in males
Prostatic carcinoma
128
- Inability of an adult male to attain an erection long enough for normal intercourse
Impotence
129
- Inability to fertilize the ovum
Infertility (sterility)
130
Special senses
- Smell
- Taste
- Sight
- Hearing
- Equilibrium
131
General senses of touch
- Temperature
| - Pressure
132
- most important of all senses; stimulus are light waves
- it is a specialized organ for photoreception (the process where in light waves are converted into nerve action potential)
Eye
133
- 70 percent of all sensory receptors are in the eyes
| - Each eye has over a million nerve fibers
The Eye and Vision
134
Protection for the eye
- Most of the eye is enclosed in a bony orbit
| - A cushion of fat surrounds most of the eye
135
Embryology of the eye (1)
- Thickening of the surface ectoderm that cause out-pocketing of the forebrain of the optic vesicle. The optic vesicle is the developing eye.
- During the early part of the 1st week of life, this optic vesicle forms a two layered optic cup. Overlying ectoderm forms a lens pit.
- During the later part of the first week of life (week 4), the optic cup deepens further and forms the inner and outer layers. The lens pit forms the lens vesicle
136
Embryology of the eye (2)
- Optic cup becomes the optic nerve of the eye
- optic cup becomes the retina. The outer layer becomes the outer layer of the retina (outer retinal pigment epithelium)
- The inner layer of the optic cup becomes the inner neural of the retina
- The lens vesicle becomes the crystalline lens
- The lens and retina are derived from the ectodem
137
Embryology of the eye (3)
- During the week 6, the lens become an internal structure and the other structures of the eye like the cornea, sclera and choroid starts to form. These structures are derived from the mesoderm
- During the 5th month of life, the all layers of the eye are already formed
138
3 Constant Layers of the Eye
- Corneoscleral coat or Fibrous Coat: outermost layer, including sclera and cornea
- Uvea: a vascular layer including choroid, ciliary body and iris
- Nervous Coat: includes the retina and its layers namely outer pigment epithelium, inner neural retina
139
- not part of the 3 layers but part of the eye
| - it is a biconvex structure, transparent structure
Lens
140
- occupies the posterior 5/6 of the eye; tough structure, keeps the eye rounded
- consists of dense, irregular connective tissue, making it opaque
- white color of the eye
Sclera
141
- transparent and avascular
| - covers the anterior one sixth of the eye, and is continuous with the fibrous Sclera posteriorly.
Cornea
142
5 layers of the Cornea:
1. Stratified squamous, non keratinizing corneal epithelium - outermost layer
2. Bowman’s membrane
3. Corneal stroma (substantia propria)
4. Descemet’s membrane
5. Simple squamous, the corneal endothelium (innermost layer) - is where transparent corneal stroma merges with opaque, vascular sclera
143
Choroid expands anteriorly to become the __.
Ciliary Body
144
- covers the lens partly; producing a central opening called the Pupil
- extends over the anterior surface of the lens from the anterior border of the ciliary body
- the one that gives color to the eye
Iris
145
__ is where transparent corneal stroma merges with opaque, vascular sclera
Limbus or corneoscleral junction (CSJ)
146
- body extends inwards to form a ring-like thickening
- With ciliary processes on its anterior third suspensory ligament of the lens (zonular ligament) arises from ciliary process
- continues posteriorly until it merges with the retina at ORA SERRATA
Ciliary Body
147
- innervated by the free nerve endings that triggers the blinking reflex
-
Corneal Epithelium
148
- basement membrane of the corneal epithelium
| - tough structure and the one that protects the eye from infection
Bowman's membrane
149
- consists majority of the cornea
- made up of about 60 layers of type I collagen fibers alternating with flattened cells (fibroblast) specifically called keratinocytes
Corneal Stroma (Substantia propia)
150
- also known as posterior limiting membrane because it serves as a basement membrane of the inner layer of the corneal epithelium.
- posterior surface
Descemet’s membrane
151
- innermost layer of the cornea is a single layer of squamous epithelium
- posterior surface
Corneal endothelium
152
- important area in the stroma of the limbus; receives aqueous humor from anterior chamber
Scleral venous sinus or Canal of Schlemm
153
- Consists mainly of choroid (has a dark brown color because of the presence of melanocytes)
- Melanin pigment, which helps to reduce glare within the eye
- Many venous plexuses and capillaries
- the one that supplies oxygen and nutrients to the retina
Uvea
154
- extends inwards to form a ring-like thickening
- With ciliary processes on its anterior third
- SUSPENSORY LIGAMENT OF THE LENS (ZONULAR LIGAMENT) arises from ciliary process
- Ciliary body continues posteriorly until it merges with the retina at ora serrata
Ciliary body
155
Ciliary body: 2 layers
1. Ciliary muscle - smooth muscle; for visual accomodation
| 2. Ciliary process - the one that produces aqueous humor
156
- fibers that holds the lens in place; arises from the ciliary process
Suspensory ligament of the lens (Zonular ligament)
157
How does visual accommodation takes place?
- Changes in the tension on the zonular fibers brought about by either contraction or relaxation of the smooth muscles bring about visual accommodation; ciliary muscle allows visual accomodation
* when the eyes are at rest or you are seeing far objects, your ciliary muscle relaxes and you have a flat lens
* if you are seeing near objects, the ciliary muscle contract sand the lens are more rounded
158
- extends over the anterior surface of the lens from the anterior border of the ciliary body
- most anterior component of the uveal tract partially covering the lens producing the central area called the pupil
- responsible for regulating the amount of light that enters the retina
- it either dilates or constricts the pupil that prevents glaring of the eye
- gives color to the eye
Iris
159
2 Sublayers of the Cornea
1. suprachoroidal lamina- outer layer; adjacent to the sclera; one that contains melanin pigment
2. choroidocapillary lamina - adjacent to the retina; the one that is rich with blood vessels that supplies the inner retina
160
Between the choroid and retina is a thin membrane called __.(you don't see this under the light microscope)
Bruch's layer
161
Iris: Consists of 5 layers
1. A discontinuous layer of fibroblasts and melanocytes (anterior part, walang epithelium)
2. The avascular anterior stromal sheet (lamella)
3. A vascular layer of loose connective tissue forming the bulk of the iris
4. The posterior membrane, containing the circular sphincter pupillae and radial dilator pupillae muscles
5. A double layer of pigmented epithelium (posterior, double pigmented epithelium)
162
- a layer of iris where you can see fibrobrast and melanocytes; the one that gives color to the eye
- the amount of melanocytes in the determines the color of the eye
- the more numerous the number of melanocytes, the darker the color of the eye; the lesser melanocytes will show, green, blue , gray, brown and black
Anterior Stromal Chamber (Iris Stroma)
163
- group of individuals where the iris is pink because of the absence of melanocytes; why pink? because it's just the reflection of the blood vessels of the eye
Albino
164
- a layer of the iris it contains the sphincter pupillae (constricts the eye) and dilator pupillae muscles (dilates the eye)
Posterior membrane
165
- inner layer of the eye; also known as the nervous coat
- has 2 major layers
1. Neural retina
2. Outer pigmented layer or outer retinal pigment epithelium (RPE)
Retina
166
4 Major cells of the retina
1. Pigmented retinal epithelium cells (outermost) - single layer of cuboidal cells; one that is adjacent to the choroid
2. Photoreceptor Cells (Rods and Cone) - most important cells of the eye
3. Bipolar Cells - intermediate cells
4. Ganglion Cells- innermost neuron of the eye
167
Parts of the Nerve Cells
Cell body - the one that receives the stimuli
Dendrites - elongated processes; the one that receives stimuli from other cells
Axon - single process; one that conducts nerve impulses to the other cells
168
10 Layers of the Retina
1. Pigment epithelium- outermost layer
2. Rods and cones cell layer
3. Outer Limiting Membrane
4. Outer Nuclear
5. Outer plexiform
6. Inner Nuclear
7. Inner Plexiform
8. Ganglion cell
9. Nerve Fiber
10. Inner Limiting Membrane- represents the innermost
plasmalemmal lining of the Muller cells
169
- Melanin-containing cells; outermost layer
Retinal Pigment Epithelium
170
- layer that contains the cell bodies of the rods and cones
Outer Nuclear Layer
171
- Cell bodies of horizontal, amacrine, bipolar and Muller’s cells
Inner nuclear layer
172
- Cell bodies of ganglion cells
Ganglion cell Layer
173
- layer that contains the dendrites of the photoreceptor cells; Inner and outer segments of photoreceptor cells
Layer of Rods and Cones
174
- 1st synaptic layer, between photoreceptors and horizontal,
amacrine and Bipolar Cells
*yung pinagdugtungan ng dendrites ng photoreceptor cells and bipolar cells
Outer Plexiform layer
175
- 2nd synaptic layer, between horizontal, amacrine, and Bipolar Cells and Ganglion Cells
Inner Plexiform Layer
176
- layer that contains the axon of the ganglion cells
| - converge at the level of the optic disc at the posterior wall of the eye to form the optic nerve
Nerve Fiber layer
177
- Apical boundary of Muller’s cells (kung hanggang saan ang Muller Cell's)
External (Outer) Limiting Membrane
178
- Composed of the basal lamina of Muller’s cells
Internal (Inner) Limiting Membrane
179
- major supporting neuron of the retina
Muller's Cell
180
- area of the blindspot because you don't see photoreceptor cells (rods and cones cell)
Optic Disk
181
- lateral to the optic disk
- most acute vision because it contains the highest concentration of cone cells
- surrounded by macula lutea (has keratinoids which are antioxidants to protect the eye from UV rays)
Fovea Centralis
182
When the light comes in from the retina, what will happen?
It will hit first the Inner Limiting membrane, the the optic nerve fiber, ganglion cell layer until it reaches the layer of rods and cones (where you can see the visual pigment, rhodopsin and iodopsin)
183
- a series of changes within these cells triggered when light waves hit the visual pigment found in the outer segment of the rods and cone cells
(yung light response is pabalik until it reaches the nerve fiber layer then nerve impulse goes to the brain via optic nerve for interpretation of the visual impulse)
Photo transduction
184
- contains melanocyte and a single layer of cuboidal cells
- serves as part of the blood-retinal barrier
- absorbs scattered light
- phagocytosed shed components of the rods and cones cells for retinal degeneration
- removes free radicals
Retinal Pigment epithelium layer
185
Rods and Cone Cells have 3 layers
1. Synaptic region - corresponds to the outer plexiform layer of the retina; the one that synapses with the bipolar cells
2. Metabolic region - contains the cell bodies (rods and cones) plus the inner segment; protein and phospholipid synthesis plus ATP production takes place
3. Photosensitive region - generation of receptor potential takes place; area that contains the outer segments of the rods and cones (where you will find the visual pigment, rhodopsin and iodopsin)
186
- peripheral vision and during dim light vision; more numerous
Rods
187
- central vision, during bright light vision, and in color discrimination
Cones
188
The outer segments of rods and cones contain the visual pigments, __
rhodopsin and iodopsin (cone opsin)
189
Components: Dense Irregular CT
Functions:
- Supports eye shape, Protects delicate internal structures, Extrinsic eye muscle attachment site
SCLERA
190
- Two layers of epithelium with organized CT in between
| - Protects anterior surface of the eye, Major refractive medium (one that bends incoming light)
CORNEA
191
4 refractive medium of the eye
1. Cornea
2. Aqueous Humor
3. Lens
4. Vitreous Humor
192
Components: Areolar/Loos Connective Tissue; Highly vascularized
Functions:
- Supplies nourishment to Retina
- Pigment absorbs extraneous light
CHOROID
193
Components:
- Ciliary smooth mucle and Ciliary process; covered with a secretory epithelium
Functions:
- Visual accomodation, Epithelium secretes Aqueous humor, Holds Suspensory ligaament that attach to the lens
CILIARY BODY
194
Components: 2 layers of smooth muscles (sphincter and dilator pupillae) and CT with central Pupil
Functions: Controls Pupil diameter and thus the amount o light entering eye
IRIS
195
Components: Pigmented epithelial cells
Functions: Absorbs extraneous light, Provides Vitamin A for Photoreceptor cells
RETINAL PIGMENTED LAYER
196
Components: Photoreceptors, Bipolar neurons, Ganglion cells and supporting Muller cells
Functions: Detects incoming light rays; light rays are converted to nerve signals and transmitted to the brain
NEURAL LAYER OF THE RETINA
197
There are 3 chambers of the eye:
1. ANTERIOR CHAMBER, between the cornea and the iris; contains the aqueous humor
2. POSTERIOR CHAMBER, between the posterior surface of the iris and the anterior surface of the lens; contains the vitreous humor
3. VITREOUS SPACE, between the posterior surface of the lens and the neural retina
198
- Watery fluid found in chamber between the lens and cornea
- Similar to blood plasma
- Helps maintain intraocular pressure
- Provides nutrients for the lens and cornea
- Reabsorbed into venous blood through the canal of Schlemm (dito lumalabas ang fluid kaya pag may bara, tataas ang intraocular pressure leading to glaucoma)
- Produced by the Ciliary process of the ciliary body
Aqueous humor
199
- Gel-like substance behind the lens
- Keeps the eye from collapsing
- Keeps the three layers of the eye tightly apposed
- Lasts a lifetime and is not replaced
Vitreous humor
200
Layer of the ciliary process that produces aqueous humor
Nonpigmented layer
201
Flow of the Aqueous Humor
Unpigmented layer of ciliary process >>
Aqueous humor in posterior chamber >>
Passes through pupillary aperture >> Aqueous humor in anterior chamber >> Drains via sclera venous sinus (Canal of Schlemn) >> scleral veins >> anterior ciliary veins
>> ophthalmic veins >> Cavernous sinus
202
- Transparent, avascular, biconvex structure, suspended by suspensory ligament of the lens
Lens of the eye
203
3 components of the Lens:
- LENS CAPSULE - produced by anterior lens cells; attachment of zonular fibers
- A SUBCAPSULAR EPITHELIUM, a cuboidal/columnar layer of cells that is only present on the anterior surface of the lens
- LENS FIBRES derived from the subcapsular epithelial cells; composed of differentiating lens fibers and mature lens fibers
204
Differentiating lens fibers (DLF) still have their nuclei, but
are greatly elongating and filling their cytoplasm with
proteins called __.
crystallins
205
- have lost their nuclei and become densely packed to produce a unique transparent structure
Mature lens fibers (MLF)
206
Accessory Structures of the Eye
1. Conjunctiva
2. Eyelids
3. Lacrimal Gland
207
- Thin, transparent mucous membrane
- Lateral margin of cornea
- Across sclera
- Covering internal surface of eyelids
- Stratified columnar epithelium, containing many goblet cells, that rests on a lamina propria of loose connective tissue
* thin membrane lining the inner surface of the eyelid (composed of upper and lower eyelid_
Conjunctiva of the Eye
208
Lining Epithelium of the Cojunctiva
Stratified columnar epithelium with Goblet cells (secretes mucus that helps in lubricating the eye)
209
Inflammation of the conjunctiva; also called pink eye
Conjuctivitis
210
– modified sebaceous glands produce an oily secretion to lubricate the eye
Meibomian glands
211
Eyelid (Layers)
1. Skin covering its external surface and smooth conjunctiva lining its inner surface.
2. Hair follicles for the eyelashes.
3. Striated muscle: most important structure of the eye lid
upper: levator palpebrae muscle (elevates/open the eye)
and orbicularis oculi muscle (closes the eye lid) and thick plate of fibroelastic connective tissue TARSUS.
212
What do you see in tarsus?
Large sebaceous glands, the tarsal glands (aka
| Meibomian glands), with acini secreting into long central ducts
213
- small sebaceous gland that is present in the eyelids
Gland of Zeis
214
- are modified apocrine sweat glands (watery secretion); produces part of the component of tear
Ciliary glands of the eyelid or Glands of Moll
215
- the one that produces the most component of tear
| - has a morphology similar to salivary glands which is compound tubulo-acinar
Lacrimal Gland
216
Lacrimal Apparatus:
Lacrimal Gland- produces lacrimal fluid
| Lacrimal Canals- drains lacrimal fluid from eyes
217
- opacity of Lens; age related; from transparent lens nagiging opaque
Cataract
218
- increase in intraocular pressure commonly due to blockage of the canal of schlemm
Glaucoma
219
Keratitis vs Scleritis
Keratitis - inflammation of of the cornea
| Scleritis - inflammation of the sclera
220
Hordeolum (Stye) vs Chalazion (Meibomianitis)
HORDEOLUM (STY)- gland of Zeis
| CHALAZION (MEIBOMIANITIS)- Meibomian gland
221
- Houses two senses
1. Hearing
2. Equilibrium (balance)
- Receptors are mechanoreceptors
- Different organs house receptors for each sense
Ear
222
The ear is divided into three areas
1. Outer (external) ear
2. Middle ear
3. Inner ear
223
- Involved in hearing only
- Structures of the external ear: Pinna (auricle); External auditory canal
- Narrow chamber in the temporal bone
- Lined with hairy skin
External Ear
224
- irregular, funnel shaped plate of elastic cartilage, covered tightly by adherent skin, which directs sound waves to the ear
Auricle or Pinna
225
Sound waves enter the external acoustic meatus, a canal lined with __ that extends from the auricle to the middle ear.
stratified squamous epithelium
226
Near its opening hair follicles, sebaceous glands, and modified apocrine sweat glands called __ are found in the submucosa
ceruminous glands
227
- the waxy material formed from secretions of the sebaceous and ceruminous glands, contains various proteins, saturated fatty acids, and sloughed keratinocytes
and has protective, antimicrobial properties.
Cerumen
228
- Narrow chamber in the temporal bone
- Lined with hairy skin
- Ceruminous (wax) glands are present
- Ends at the tympanic membrane
External Auditory Canal
229
- Air-filled cavity within the temporal bone
| - Only involved in the sense of hearing
Middle Ear or Tympanic Cavity
230
Two tubes are associated with the inner ear
1. The opening from the auditory canal is covered by the tympanic membrane
2. The auditory tube or eustachian tube connecting the middle ear with the throat/nasopharynx
231
Function of Eustachian Tube/Auditory Tube
- Allows for equalizing pressure during yawning or swallowing
- This tube is otherwise collapsed
232
Middle Ear or Tympanic Cavity: Borders
Lateral wall – tympanic membrane
Roof and floor – temporal bone
Posterior wall – temporal bone leading to mastoid antrum thru w/c air passes to mastoid air cells
Medial wall – thin layer of temporal bone with 2 openings
*Oval window
*Round window
233
Three bones span the cavity (Auditory Ossicles)
1. Malleus (hammer)
2. Incus (anvil)
3. Stapes (stirrup
*these bones amplify sound waves; vibration of the tympanic membrane >> will move the 3 auditory ossicles >> transmit the sound to the inner ear
234
- Includes sense organs for hearing and balance; a maze of bony chambers within the temporal bone
- made up of cochlea, vestibule and semicircular canal
- innervated by the vestibular and cochlear division of the cranial nerve (CN VIII) that transmits impulse to the brain for interpretation
Inner Ear
235
The inner ear consists of 2 labyrinthine compartments
1. Bony (osseous) labyrinth: in the petrous portion of the
temporal bone — PERILYMPH (fluid inside the bony labyrinth)
2. Membranous labyrinth: within the bony labyrinth —
ENDOLYMPH (fluid inside the membranous labyrinth)
236
Bony (osseous) labyrinth
- VESTIBULE: the central space of the bony labyrinth
- SEMICIRCULAR CANALS: extending from the vestibule posteriorly
- COCHLEA: extending from the vestibule anteriorly
237
Membranous labyrinth
- UTRICLE AND SACCULE, connected by the utriculosaccular duct (balance)
- Membranous SEMICIRCULAR DUCTS, within the semicircular canals (balance
- Membranous COCHLEAR DUCT, within bony cochlea, continuous with saccule (hearing)
238
- Awareness of the position and movement of the head
- Receptors:
1. Maculae
2. Cristae Ampullaris
EQUILIBRIUM / VESTIBULAR SENSE
239
- located in the epipthelial wall utricle and saccule
- receptors in the vestibule
- Report on the position of the head
- Send information via the vestibular nerve
- for static equilibrium (it detects the position of the head at rest, tilt and linear acceleration)
MACULAE
240
Anatomy of the maculae
- HAIR CELLS are embedded in the otolithic membrane; has a kinocilium, stereocilia; innervated by vestibular branch of CN VII; has also microvilli (supporting cells)
- OTOLITHS (TINY STONES) FLOAT in a gel around the hair cells
- Movements cause otoliths to bend the hair cells
241
__ are covered by Otolithic membrane which has otolighs (tiny stones) that facilitates bending of the hair cells.
Kinocilium, stereocilia and microvilli
242
When the head is at rest or you move forward
- gagalaw iyong hair cells due to the pressure developing in the otolithic membrane
- when the hair cells move, gagalaw din ang vestibular branch ng CN VIII. This impulse is delivered to the brain for interpretation kung anong movement ang ginawa mo
- eg Zigzag road in Baguio - it stimulates the macula
243
When you passed by a zigzag road, your macula is overtimulated which causes __. Kasi sunod sunod ang pumamasok na impulse, nalilito ang brain.
Motion sickness
244
- are crystalline structures in the outer part of the otolithic
membrane.
- Composed of calcium carbonate on a matrix of
proteoglycans
- Facilitates bending of the kinocilia and stereocilia
embedded in this membrane by gravity or movement of
the head
Otoliths
245
2 TYPES OF HAIR CELLS
1. TYPE I HAIR CELLS: basal ends are rounded and
enclosed within a nerve calyx on the afferent fiber
2. TYPE II HAIR CELLS: are columnar and associated
with typical bouton synaptic connections to their
afferents
246
- receptors in the semicircular canals
- Tuft of hair cells
- Cupula (gelatinous cap; innervated by the vestibular branch of CN VIII) covers the hair cells
- detects angular and rotational movement of the head
CRISTA AMPULLARIS
247
Angular or rotational movement of the head
- The cupula stimulates the hair cells >> pressure is built up in the cupula (kasi ang laman nito is endolymph)
- An impulse is sent via the vestibular nerve to the cerebellum
248
- Overstimulation of the crista ampullaris (over rotation movement) you will develop __
Vertigo
249
• bony cochlea
HEARING / AUDITION
250
Three compartments of the Cochlea
1. the upper, scala vestibuli
2. the lower, scala tympani
3. the middle, scala media
251
The upper, scala vestibuli and the lower, scala tympani contain __
Perilymph
252
The middle, scala media contains
Endolymp
253
- Located within the cochlea
- Receptors = hair cells on the basilar membrane
- Gel-like tectorial membrane is capable of bending hair cells
- Cochlear nerve attached to hair cells transmits nerve impulses to auditory cortex on temporal lobe
- Rests on the basilar membrane
Organ of Corti
254
- separates the scala vestibule from scala media
vestibular membrane (Reissner’s membrane)
255
- Projects over the organ of Corti; the one that moves the hair cells pag may pumasok na sound waves; similar to the cupula
Tectorial membrane
256
Mechanisms of Hearing
- Sound waves will enter into the pinna -> pass through the auditory canal -> vibration of the tympanic membrane (amplification of sound) -> transfers the sound to the inner ear via the oval window -> scala vestibuli -> vibration of vestibular membrane -> hair cells of organ of corti are stimulated -> Cochlear nerve via CN VIII for interpretation
* the excess sound wave will go through the scala tympani and exits via the round window
257
Different sound frequency will stimulate different area of the the cochlea is stimulated
* high frequency sounds - stimulates the base of the cochlea (basilar membrane of the cochlea)
* medium sound waves -central region
* base sound waves - apical end of the cochlea
258
Organ of Corti: two types of cells
* Supporting cells - tall, slender cells extending from the basilar membrane to the free surface of the organ of Corti. *Outer and inner pillars, inner and outer phalangeal cells, and cells of Hensen.
* Hair cells.
259
- perilymphatic space above the scala media
- communicates with the vestibule
- lined on both sides by simple squamous epithelium
- vestibular membrane (Reissner’s membrane) separates the scala vestibule from scala media
Scala vestibuli
260
- Triangular endolymphatic space between the scala vestibule and scala tympani
- Lateral wall bounded by a highly vascular stratified epithelium – stria vascularis (responsible for
production and maintenance of endolymph)
Scala media / cochlear duct
261
- Perilymphatic space below the scala media
Scala tympani
262
- located in the lateral wall of the cochlear duct which produce and maintains the endolymph
Striae Vascularis
263
conduction deafness vs sensorineural deafness
Conduction - involves the middle ear; usually due to impacted cerumen
Sensorineural - loss of hair cells or degeneration specifically the cochlear division of the CN VIII
264
- comprise of hearing loss, vertigo and tinnitus
MENIERE’S SYNDROME
265
- sensation of movement around space
| - could be peripheral (involves inner ear), central (involves the CNS) or psychogenic (all in the mind/psychological)
VERTIGO
266
- inflammation of the middle ear
OTITIS MEDIA
267
LABYRINTHITIS vs MYRINGITIS (TYMPANITIS)
LABYRINTHITIS - inflammation of the inner ear
| MYRINGITIS(TYMPANITIS)- inflammation of the eardrum or tympanic membrane
268
• Olfactory receptors are in the roof of the nasal cavity
- Neurons with long cilia
- Chemicals must be dissolved in mucus for detection
• Impulses are transmitted via the olfactory nerve
• Interpretation of smell is made in the cortex
Olfaction – The Sense of Smell
269
Cells of the Ofactory
1. Olfactory Cells
2. Sustentacular Cells/Supporting Cells
3. Basal Cells
270
Lining of the Olfactory Epithelium
Pseudostratified Columnar Epithelium
271
Glands in Olfactory epithelium
Bowman's Gland - are serous glands that produces the moist fluid that dissolves the substances/chemicals before they are interpreted
272
Taste buds house the receptor organs
Sense of Taste
273
Location of taste buds
- Most are on the tongue
- Soft palate
- Cheeks
274
The tongue is covered with projections called papillae
- Filiform papillae – sharp with no taste buds
- Fungiform papillae – rounded with taste buds
- Circumvallate papillae – large papillae with
taste bud
275
- are the receptors
- Have gustatory hairs (long microvilli)
- Hairs are stimulated by chemicals dissolved in
saliva
Gustatory cells
276
Impulses are carried to the gustatory complex by
several cranial nerves because taste buds are found in
different areas
- Facial nerve
- Glossopharyngeal nerve
- Vagus nerve
277
3 Types of Cells in the Taste Buds
1. Gustatory Cells
2. Supporting Cells
3. Basal Cells
278
* general term of acute inflammatory disease of the upper respiratory tracts such as nasal cavity, tonsils, pharynx and larynx etc.
* Upper Respiratory tract includes the nose, pharynx, larynx, sinuses and trachea.
Common Cold Syndrome
279
Common Cold Syndrome: Signs and Symptoms
* Sore throat
* Runny nose- respiratory epithelium (ciliated pseudostatified columnar epithelium with goblet cells) which increases the secretion of mucus via goblet cells which will cause nasal congestion and sneezing
* Conjunctivitis (inflammation of the conjunctiva) , myalgias (muscle pain) and fatigue
* Sinusitis (inflammation of the sinus), Rhinosinusitis
* Nasopharyngitis
280
– inflamed part of the pharynx affected due to the presence of the Waldeyers Ring or lymphoid tissue protecting the entry portals of the respiratory and gastrointestinal tract.
Nasopharyngitis
281
- common in children due to the Eustachian tube (short and wide lumen in children) which connects the ear and nose. Therefore secretions from the nasal cavity can enter the ear.
Otitis media
282
- Upper Respiratory tract includes the nose, pharynx, larynx, sinuses, and trachea.
URTI (Upper Respiratory Tract Infection)
283
SPECIAL SENSES
- Hearing
- Sight
- Smell
- Taste
- Touch
- Balance
284
This 3 symptoms: choraiza, conjunctivitis, colds and cough were particularly present usually with __
measles or rubeola
285
Etiology of Common Colds
```
1. Viral
• Rhinovirus (early fall)
• Coronavirus (winter)
• Human Respiratory Syncytial virus (RSV) - most common cause of respiratory tract infection among Filipino children.
2. Bacterial
• S. pneumoniae
• H. influenzae
• M. catarrhalis - from the nasopharynx
3. Immune system
4. Environmental Factors
```
286
Pathology
- Invasion of the lining epithelium/mucosa (ciliated
pseudostatified columnar epithelium with goblet cells)by
the pathogen causes inflammation and infection .
- Reason for the sign and symptoms which results to
clogging thus decreasing the sense of smell .
287
Pathways of Smell
1. Nostrils – contains the olfactory receptors
2. Nasopharynx – (roof of the mouth) when you chew food, aroma release by food which will be chemically sensed by the ofactory receptors
3. Common chemical sense – nerve endings found in the mucosa of eyes, nose, mouth, and throat.
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* contains receptor cells for olfaction
* highly sensitive up to 10,000 odors
* on 5 cm2 of the superior concha and nasal septum
* LE: pseudostratified columnar ciliated epithelium without goblet cells
Olfactory mucosa
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Olfactory Pathway
Stimuli---Nose----Olfactory receptors----CN 1--- Limbic
| system--- interpretation of odor
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Hyposmia vs Anosmia
Hyposmia – reduced ability to detect odors
| Anosmia – complete inability to detect odors
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Parosmia vs Phantosmia
Parosmia – change in the normal perception of smell
| Phantosmia – sensation of an odor that isn’t there
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Common Causes of Smell Disorders (1)
• Aging- normal to elderly
• Head injury- special senses located in the face
• URTI- infection
• Hormone- eg. In female secretory phase of ovulation=
increase of progesterone
-Pregnancy especially first trimester= increase in progesterone (craving when period comes)
• Smoking
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Common Causes of Smell Disorders (2)
* Dental problem due to dental carries which alters the sense of taste
* Tumor/growth
* Radiation Rx- destroys cells or receptors of olfactory
* Medications- inhalers ( vicks and white flower)
* Chemicals
* CNS conditions
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Tongue: Parts
Tip: Sweet
Lateral: Sour and Salty
Posterior: Bitter
Spicy taste: free nerve endings (receptors for pain)
(myth)
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- the chemoreceptors for the sense of taste
| (gustation) .
Taste Buds
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Classically, 2 types of cells are described in the taste bud:
1. light gustatory cells
2. dark supporting/sustentacular cells
3. A third cell type,a basal cell, is now generally recognized and may constitute the precursor of one or both of the other cell types.
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– lingering; There are patients who have problem in their tongue or taste buds especially as they age, they tend to have higher salt taste.
Phantom taste perception
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– reduced ability to taste
- If you want to taste your soup, you must have 3 teaspoons to know the taste
- geusia means “you need more”; ageusia means “loss
of taste”
- If you have ageusia more or less you have anosmia; if
you have anosmia more or less you have ageusia.
- If the patient comes to you complaining of problems in
taste, you should ask for history of their medication. Antihypertensive
drugs can cause taste disturbances.
Hypogeusia
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Ageusia vs Dysgeusia
Ageusia – true taste loss
| Dysgeusia – persistent unpleasant taste in the mouth
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Causes of taste problem
- URTI - infection
- Radiation Rx
- Exposure to certain chemicals
- Head Injury
- Surgeries
- Poor oral hygiene & dental problems - dental caries.
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- Eyes is a specialized organ of photoreception (process of
conversion of light energy to electric energy/action
potential)
Sense of Sight
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Consists of photoreceptors: 2 types
* Rod cells – Perceived images in a black and white photographic form (if it is night yan nag wowork)
* Cone cells- has 3 functional types each are either receptive to colors blue/ green/ red, and constitutes a system that perceived colored images.
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Sensory of the Eyes
Sensory goes inner so light -> refracted by the cornea -> pupil -> further refracted by the lens-> inverted image is projected to the retina.
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- Separation of the retinal layers; symptoms include loss of vision corresponding to the detached part of the retina this is described as ‘like a dark curtain’ in the visual field.
Retinal detachment
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- Sustained increase in IOP (intraocular pressure) due to obstruction of the drainage of aqueous humor and continuous secretion of the ciliary body; the cause may be by genetic abnormality at the canal of Schlemm, diseases which causes inflammation/ scarring of the irdocorneal angle -> blocks the canal of Schlemm
- Proliferation of blood vessels in the iris root (usually due to poor blood supply to the retina, common to diabetic patients.
Glaucoma
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- Damage to lens fibers or aggregation of crystalline proteins that turns the lens opaque, this leads to diffused or blocked light; the cause of this can be due to aging, trauma or inflammatory disease.
Cataract
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- caused ny disorders that interfere with the conduction of sound through the outer and middle ear, affecting hearing before he sound reaches the cochlea.
Conductive Deafness
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- inherited disease where the ossicles fuse together, preventing conduction of sound. Surgery can reestablish conduction and restore hearing.
Otosclerosis
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- caused by damage to the sensory receptors of the inner ear (the hair cells, organ of Corti) or the auditory nerve leading to the brain.
Sensory-neural Loss
