Anatomy 27 Flashcards
(115 cards)
1
Q
What is the Vas deferens?
A
A tube that carries sperm from the epididymis up the spermatic cord and through the inguinal canal into the pelvis
2
Q
Where does the vas deferens pass?
A
From the deep inguinal ring, the vas deferens passes across the side wall of the pelvis, then turns medially onto the back of the bladder
3
Q
How does the vas deferens terminate?
A
By joining the duct of the seminal vesicle to form the ejaculatory duct
4
Q
What are the seminal vesicle?
A
Lobulated sac, about 4cm long, lying lateral to the ampulla of the vas deferens
5
Q
What do the seminal vesicles secrete?
A
Thick alkaline fluid which forms the bulk of seminal fluid (also known as semen)
6
Q
What forms the ejaculatory duct?
A
The duct of the seminal vesicle joins the vas deferens
7
Q
Where does the ejaculatory duct enter the prostatic gland?
A
Pierces the back of the prostate gland to enter the prostatic urethra
8
Q
What is the prostate gland?
A
Roughly spherical fibromuscular gland about the size of a walnut
9
Q
Where does the prostate gland lie?
A
It lies against the neck of the bladder and is pierced by the urethra and ejaculatory ducts
10
Q
What happens to secretions of the prostate?
A
They are added to the seminal fluid during ejaculation
11
Q
What supplies the Vas deferens, seminal vesicles and prostate?
A
Branches of the internal iliac artery
12
Q
What is the ‘benign prostatic hyperplasia’ (BPH)?
A
Enlargement of the prostate with progressing age
13
Q
What can BPH lead to?
A
Compression of the urethra and the inability to pass any urine - called urinary retention
- which requires catheterisation (insertion of a catheter into the bladder) to drain the urine
14
Q
How does prostate cancer metastasise?
A
Venous blood from the prostate passes into a plexus of veins which lie anterior to the sacrum and communicate with veins which run up to the azygos vein in the chest.
These veins communicate with veins in the vertebral bodies which explains why prostate cancer commonly metastasizes to the vertebrae
15
Q
How can the prostate be examined?
A
A digital rectal exam (DRE), also known as a ‘per rectum’ exam (PR).
This involves pushing a finger into the rectum via the anus and flexing it anteriorly to palpate the prostate which sits immediately anterior to the anal canal and rectum.
A clinician can feel the size, contour and firmness of the prostate during this exam and this can help guide diagnosis.
A hard, craggy prostate is concerning for malignancy
16
Q
What does the female pelvis contain?
A
The uterus, cervix, vagina, the uterine tubes and ovaries
17
Q
What is the uterus?
A
A hollow muscular organ about 8cm long
18
Q
What does the uterus communicate with?
A
Laterally with the uterine tubes and
Inferiorly with the vagina
19
Q
What are the different parts of the uterus?
A
Fundus (above the uterine tubes),
a body and a cervix
20
Q
What is the body of the uterus?
A
The body of the uterus is typically angled anteriorly (ante-flexed) and lies on the superior surface of the bladder.
21
Q
In conception where does the developing blastocyst implant?
A
Into the uterine lining (endometrium) in the body of the uterus
22
Q
What happens to the middle muscular layer of the uterus (myometrium) as pregnancy continues?
A
It becomes distended
23
Q
What is the uterus covered in?
A
A fold of peritoneum which adheres to itself at the sides of the uterus to form the broad ligament
24
Q
What is the rectouterine pouch (Pouch of douglas)?
A
The space behind the uterus but anterior to the rectum and is lined with periotoneum
25
Why is the pouch of douglas a common site for the accumulation or intraperitoneal fluid or pus?
It is the deepest point in the peritoneal cavity
26
What is the cervical canal?
Narrow lumen, which communicates with the uterine cavity via the internal os and with the vagina via the external os
27
Where does the lower part of the cervix lie?
Inside the vagina creating a recess, the vaginal fornices, around the cervix
28
What is the position of the cervix stabilised by?
The tone of the levator ani muscle and ligaments which run from the lateral wall of the cervix to the lateral pelvic wall at the base of the broad ligament
29
What do the uterine tubes/fallopian tubes carry?
Carry ova from the ovary towards the uterine cavity
30
Where does fertilisation occur?
Inside the uterine tubes
31
Where do the uterine tubes run?
They are about 10cm long and are found running in the upper border of the broad ligament
32
What features does the uterus have near it?
Near the uterus, the tubes have a narrow isthmus.
Laterally, the uterine tubes have a dilated ampulla, leading into a funnel-shaped infundibulum
33
What is the free edge of the infundibulum broken into?
Finger-like projections, the fimbriae, which are draped over the ovary
34
What are the ovaries?
Almond-shaped organs about 4cm long and 2cm wide
35
What are the ovaries attached to?
Attached to the posterior aspect of the broad ligament by a short mesentery; the mesovarium
36
Where do the ovaries lie?
The position of the ovary is not fixed, but it frequently lies in the ovarian fossa, formed by the angle between the internal and external iliac arteries
37
What is the vagina?
The vagina is the female organ of sexual intercourse and the excretory duct of the uterus.
It is about 10cm long
38
What features does the vagina have?
It has a blind-ended vault in the region of the cervix and
terminates below at the introitus by opening into the vestibule (space) between the labia minora
39
What does the vagina pass through?
The pelvic floor; the upper two thirds of the vagina lie in the pelvic cavity and the lower one third in the perineum
40
What is the vagina closely related to?
Bladder anteriorly
41
Where is the urethra located in relevance to the vagina?
The urethra is often embedded in the anterior wall of the lower third of the vagina
42
What artery supplies the uterus, cervix, uterine tubes and vagina?
Branches of the internal iliac artery
43
What artery supplies the ovary?
Ovarian artery
44
What is the ovarian artery a direct branch of?
The abdominal aorta and contributes to the blood supply of the uterine tubes
45
What is the vulva?
Collective term for all parts of the female external genitalia
46
What is the blood supply to the vulva via?
The internal pudendal arteries (branches of the internal
iliac arteries)
47
What nerves innervate the vulva?
The ilioinguinal nerve,
The genital branch of the genitofemoral nerve,
The pudendal nerve and
The posterior cutaneous nerve of the thigh
48
What are the erectile tissues innervated by?
Parasympathetic nerves
49
What are the mons pubis?
Mound of fatty tissue located in front of the pubic symphysis causing an elevation of the hair-bearing skin
50
What is the labia majora?
Prominent hair-bearing folds of skin that meet at the mons pubis anteriorly
51
What is the labia minora?
* Smaller, hairless folds of skin located medial to the labia majora
* Fuse together anteriorly to form the hood of the clitoris
* Form the boundaries of the vestibule
52
What is the clitoris?
* Pea-sized, highly sensitive tissue comprised of the erectile corpora cavernosa and corpus spongiosum
* Becomes engorged during sexual arousal
53
What is the vestibule?
* Area between the labia minora
* Contains the vaginal opening, urinary meatus and vestibular glands
54
What is the vaginal opening?
Entrance to the vagina
Also known as the vaginal introitus
55
What is the hymen?
* Thin membrane that partially covers the vaginal opening
* Often ruptures during the first episode of sexual intercourse and historically its presence was taken as proof of virginity.
However, it can rupture spontaneously, during exercise, by using tampons or menstrual cups, or it may simply be absent altogether
56
What is the urinary meatus?
* Opening of the urethra
* Lies posterior to the clitoris, but anterior to the vaginal opening
57
What are the greater vestibular glands?
Greater vestibular glands
- also known as Bartholin’s glands -
They lie just posterior to the vaginal opening and secrete a lubricant into the vagina during sexual arousal
58
What are the lesser vestibular glands?
Lesser vestibular glands
- also known as Skene’s glands -
They lie near the urethral opening.
The function of the fluid they secrete is debated but it may lubricate the vaginal opening or urethra or have an antimicrobial effect.
59
When does an ectopic pregnancy occur?
Occurs when the blastocyst implants outside the uterus
60
Where is the most common place for an ectopic pregnancy to occur?
Uterine tube
61
What happens in an ectopic pregnancy?
Fertilisation usually occurs in the uterine tubes and the zygote is swept down the uterine tubes towards the
uterus by ciliated cells.
If the zygote does not reach the uterus it may implant in the wall of the uterine tube.
The uterine tube cannot stretch to accommodate a growing embryo and so may rupture.
This can cause significant pain and internal bleeding and can be life-threatening.
A tubal pregnancy cannot progress, and surgery is required to remove the pregnancy from the uterine tube.
62
What is endometriosis?
A condition in which endometrial tissue, which lines the inside of the uterus, is found outside the uterus
63
What do endometrial deposits affect?
The ovaries, uterine tubes, uterine ligaments and rectouterine pouch
64
What can endometriosis lead to?
Can lead to chronic pelvic pain, cyclical pain related to menstruation and pain during intercourse
65
What was endometriosis formally diagnosed using?
Biopsy samples obtained during surgical exploration (diagnostic laparoscopy)
66
What are symptoms of gynaecological cancers?
Symptoms may include pelvic pain, abnormal vaginal discharge, abnormal vaginal bleeding (bleeding between periods, after intercourse or after the menopause), urinary disturbance, abdominal swelling and more non-specific symptoms of malignancy such as fatigue and weight loss
67
What happens in a cervical smear test?
This involves taking a sample of cells from the cervix to see if particular types of human papillomavirus (HPV) – which are associated with the development of cervical cancer - are present
68
What is the urinary bladder?
A hollow muscular organ located in the pelvis below the peritoneum, therefore it is classed as an infraperitoneal organ
69
Where is the urinary bladder located?
Posterior to the pubic symphysis, and anterior to the vagina and rectum
70
What is the urinary bladder supplied by?
By the vesical arteries which are branches of the internal iliac artery
71
What is the function of the urinary bladder?
It stores urine and helps to squeeze the urine out during micturition
72
What is the bladder filled with?
Urine from the ureters which drain into the posterior aspect of the bladder near the base
73
What is the trigone of the bladder?
Triangular area with a smooth wall
74
Where does the ureter enter the trigone?
Ureters enter the trigone of the bladder at an angle, forming a rudimentary valve which prevents reflux of urine into the ureters when the bladder is full
75
What is the inside wall of the bladder corrugated with?
Corrugated with folds of mucosa called rugae which allow the bladder to stretch without tearing when it fills
76
What type of muscle does the bladder wall contain?
Contains smooth muscle - the detrusor -
which contracts to forcibly expel urine
77
What is release of urine controlled by?
Internal and external urethral sphincters
78
What is internal urethral sphincter?
The internal urethral sphincter is located at the base of the bladder where it opens into the urethra.
It is composed of smooth muscle and is under involuntary control.
79
What is the external urethral sphincter?
The external urethral sphincter is located just after the prostate in males, and in the deep perineal pouch in females.
This sphincter is composed of skeletal muscle and is under voluntary control.
80
What is the somatic innervation of the Urinary Bladder and Urethral Sphincters?
* Via branches of the pudendal nerve (S2-S4)
* Allows conscious control of the external urethral sphincter
81
What is the sympathetic innervation of the Urinary Bladder and Urethral Sphincters?
* Via branches of the hypogastric nerve (sympathetic chain, T12-L2)
* Causes relaxation of the detrusor and contraction of the internal urethral sphincter, allowing storage of urine
82
What is the parasympathetic innervation of the Urinary Bladder and Urethral Sphincters?
* Via the pelvic splanchnic nerves (S2-S4)
* Causes contraction of the detrusor and relaxation of the internal urethral sphincter, allowing initiation of micturition
83
What is the urethra?
The urethra carries urine from the internal urethral orifice of the bladder to the external urethral orifice (located at the tip of the penis in males and in the vestibule in females)
84
What does the male urethra also contain?
Semen
85
How short is the female urethra?
Approx 3-4cm
86
What is the male urethra subdivided into?
Conventionally subdivided into preprostatic, prostatic, membranous and penile parts
87
What is urination controlled by?
Controlled by centres in the cerebral cortex, brainstem and sacral spinal cord
88
Where is the sacral micturition centre contained?
Sacral spinal cord
89
What is the bladder stretch reflex?
As the bladder fills, stretch of the bladder wall is detected and this is relayed to the sacral spinal cord via visceral afferent fibres.
In the sacral spinal cord these fibres synapse directly onto motor neurons.
The motor neurons (via parasympathetic fibres in the pelvic splanchnic nerves) stimulate bladder contraction.
This simple relay through the spinal cord, where bladder filling initiates bladder emptying, is a type of stretch reflex and is referred to as a reflex arc
90
What is the bladder reflex arc inhibited by?
Inputs from the cerebral cortex – older children and adults can detect bladder filling and consciously control when and where they urinate
91
What is 'potty-training'?
When infants learn to consciously recognise bladder filling and develop descending pathways that inhibit the reflex when it is not convenient to urinate
92
What pathways are interrupted if a patient suffers injury to their spinal cord above the sacral level? (Bladder dysfunction)
1. ascending pathways conveying the sensation of bladder filling to the brain (so the patient is no longer aware of bladder filling)
2. descending pathways that exert voluntary, inhibitory control over the external urethral sphincter (so the external sphincter is permanently relaxed).
The reflex arc still functions below the injury, but the patient does not have any inhibitory control over it.
The patient does not realise they need to pass urine and the bladder automatically empties as it fills, so the patient is incontinent of urine.
93
What happens if a patient suffers an injury to the spinal cord or cauda equina at or below the level of the
sacral micturition centre?
The reflex arc itself is disrupted and the bladder fills with urine without emptying.
The internal urethral sphincter is permanently contracted. As the bladder continues to fill, the pressure in the bladder eventually exceeds the strength of the internal urethral sphincter and urination will occur.
This type of incontinence is ‘overflow incontinence’.
If the pressure inside the bladder does not overcome the sphincter the patient develops urinary retention.
Eventually urine may back up to the ureters and kidneys if a urinary catheter is not placed
94
What is the rectum?
Terminal part of the large intestine
95
What features does the rectum have?
Has two notable curves, or flexures: a curve anteriorly (the sacral flexure) and a curve posteriorly (the anorectal flexure)
96
What is the primary purpose of the rectum?
Storage of faeces prior to defecation
97
What is the anal canal?
Most distal part of the gastrointestinal tract is the anal canal which is approximately 4cm long in the adult
98
Where does the anal canal extend from?
Extends from the distal rectum to the anus and lies in the anal triangle of the perineum
99
What are the 2 anal sphincters?
Internal and external
100
What is the internal anal sphincter?
Composed of smooth muscle and is involuntarily controlled
101
What is the external anal sphincter?
Composed of skeletal muscle and is voluntarily controlled
102
What does the pectinate/dentate line divide?
Divides the superior part of the anal canal from the inferior part
103
What is the superior part of the anal canal, above the pectinate line, derived from?
Endoderm
104
What is the inferior part of the anal canal, below the pectinate line, derived from?
Ectoderm
105
What is the superior part of the anal canal supplied by?
Inferior mesenteric artery (via the superior rectal artery)
106
What is the venous drainage of the superior part of the anal canal?
Via the portal venous system towards the liver
107
What is the superior part of the anal canal encircled by?
Internal anal sphincter and the lumen is lined by columnar epithelium (i.e. intestinal mucosa)
108
What is the internal anal sphincter innervated by?
Sympathetic fibres (originating from the sympathetic trunk) and parasympathetic fibres (via the pelvic splanchnic nerves)
109
What is the inferior part of the anal canal supplied by?
By the middle and inferior rectal arteries which originate from the internal iliac arteries
110
What is the venous drainage of the inferior part of the anal canal?
Venous blood enters the systemic venous system and does not pass through the portal system
111
What is the inferior anal canal encircled by?
The external (voluntary) anal sphincter which is innervated by the pudendal nerve (a somatic nerve). Stratified squamous epithelium lines the lumen.
112
What are haemorrhoids?
The walls of the anal canal are lined with an abundance of veins that form ‘cushions’ which aid faecal continence, the cushions are haemorrhoids.
113
What can happen haemorrhoids?
They can become excessively swollen and inflamed and, depending on whether they form above or below the pectinate line, they may be painless (above the pectinate line) or painful (below pectinate line)
114
What happens if haemorrhoids are pathological?
They often bleed when passing stool.
If they are painless haemorrhoids, the presence of blood on wiping or blood dripping into the toilet after
defecation may be the first sign that they are present
115
What can lead to haemorrhoids becoming swollen?
Increased intra-abdominal pressure, for example, in excessive straining, constipation, squatting or pregnancy increases pressure in the pelvic veins
