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specialised systems Flashcards

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1
Q

reproductive organs

A
  • produce gametes and secrete hormones
  • hormones control the development and function of the respiratory system
  • development of sex-specific body form
  • fertilisation and development of foetus
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2
Q

reproductive ducts

A
  • transport and store gametes
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3
Q

role of reproductive hormones

A
  • development & function of the reproductive system
  • development of sex-specific body form
  • normal sex-specific behaviour
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4
Q

accessory glands (male reproductive system)

A

produce seminal fluid

  • seminal glands
  • prostate gland
  • bulbo-urethral glands
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5
Q

gonads - testes

A

produce sperm and hormones

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6
Q

associated ducts

A

transport, store & mature sperm

  • epididymis
  • ductus deferens
  • urethra
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7
Q

external genitals

A
  • penis
  • scrotum
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8
Q

what are the testes?

A
  • paired, flattened egg shaped organs
  • develop in foetal abdomen
  • descend at 7th month of development into the scrotum
  • located in scrotum outside the body
  • 2/3 degrees cooler for sperm protection
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9
Q

function of the testes

A
  • sperm production
  • dual endocrine and exocrine
  • connected to a duct system
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10
Q

tunica albuginae

A
  • the tough fibrous layer of connective tissue that surrounds the testes
  • subdivides into 300 lobules
  • lobules made out of 1-4 siminiferous tubules
  • tubules empty into efferent ductules
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11
Q

interstitium

A

loose conective tissue that surrounds the tubules

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12
Q

tunica vaginalis

A
  • closed sac of serous membrane
  • serous fluid

contains:

  • parietal layer
  • cavity
  • visceral layer
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13
Q

the scrotum

A
  • sac
  • made of skin, connective tissue & dortos muscle
  • covered by pubic hair
  • contains the testes
  • divide internally: by ridge of CT septum
  • divide externally: by raphe/ridge
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14
Q

function of the scrotum

A
  • temperature control
  • associate muscles can contract to bring it closer to the body when cold
  • cold: contraction
  • heat: relaxarion -> testes further from the body to keep sperm cooler
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15
Q

muscles in the scrotum

A
  • dartos: reduces scrotum size by firming up skin
  • cremaster: pulls testes nearer the body, makes up middle layer of fascia around spermatic cord
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16
Q

spermatogenesis

A
  • the production of sperm from the primordial germ cells
  • 70-100 million sperm each day
  • high proliferation rate -> high mutation rate
  • takes 64 days
  • sperm stored in seminiferous tubules
  • sperm matures in the epididymis
  • controlled by the brain -> HPG axis
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17
Q

testis descent

A
  • start near kidneys
  • descend into scrotum
  • starts at 7th month in utero
  • 96-98% of boys descend normally
  • 2-4% cryptorchidism -> risk of testis cancer
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18
Q

inguinal canal

A
  • bilateral passagement anterior to abdominal wall
  • between deep and superificial inguinal rings
  • openings into abdominal muscles
  • contains:
    -> ilionguinal nerve
    -> spermatic cord
    -> arteries, nerves & veins
    -> vas deferns
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19
Q

inguinal canal - herniae

A

opening can create weakness -> hernia

  • fatty tissue of bowel can protrude through a weakness in the abdominal wall
  • creates a visible lump
  • can be painful
  • more visible when lifting
  • can obstruct / stranulate the bowel -> surgery
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20
Q

spermatic cord

A
  • vessels & ducts running to / from testes
  • runs through inguinal canal to scrotum
  • covered in fascia
    -> cremaster muscle makes up middle layer of fascia around spermatic cord -> contractes to pull testes up
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21
Q

what does the spermatic cord contain?

A
  • vas deferns
  • lymph vessels & autonomic nerves
  • testicular aterty & pampiniform plexusof testicular veins
  • cremasteric artery & vein
  • deferential artery
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22
Q

epididymis

A
  • coiled tube
  • head, body & tail
  • pseudostratified columnar epithelium encircles by smooth muscle
    lined by cilia
  • microvilli increase s.a.
  • reabsorb & recycles degenerate sperm
  • protection & storage
  • provides adequate sperm concentration
  • unable to fertilise eggs
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23
Q

ductus (vas) deferens

A
  • strong muscular tube
  • part of spermatic cord
  • transport sperms cells from the respective epididymis to the ipsilateral ejaculatory duct.
  • lined by pseudostratified columnar epithelium
  • stereocilia
  • ascends from epididymus, through inguinal canal to pelvis
  • enlarges posteriorly and proximally as the ampulla
  • joins seminal vesicle duct = ejaculatory duct
  • empties into prostatic urethra
  • cute & ligated in vasectomy
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24
Q

seminal vesicles

A
  • paired glands
  • in the male reproductive system
  • posterior / inferioir to urinary bladder
  • smooth muscle wall -> contraction empties semen during ejaculation
  • pseudostratified columnar epithelium with secretory cells
  • produces and stores semen (60%)
  • fructose and prostaglandins
  • alkaline secretion
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25
Q

prostate gland

A
  • inf to bladder
  • donut shaped aorund prostatic urethra
  • smooth muscle gland -> smooth muscle contraction
  • 30% of semen
  • secretions: lightly alkaline, liquifes the semen
  • prostate-specific antigen
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26
Q

prostate gland diseases

A
  • prostatis
  • benign hyperplasia
  • prostate cancer
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27
Q

bulbourethtral (cowper´s) glands

A
  • paired
  • inf to prostate
  • empties into spongy urethra
  • alkaline mucus secretion
    -> neutralise urine in urethra & lubricates
    -> protects sperm during ejaculation
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28
Q

urethra

A
  • urinary & reproductive function
  • 3 segments:
    -> prostatic= gets ejaculatory & prostatic ducts
    -> membranous
    -> spongy= gets blubourethtral gland ducts
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29
Q

penis

A
  • root and bulb -> connects penis to pelvic bones
  • shaft = columns of erectile tissue
    -> blood sinuses
    -> corpus spongiosum - ventral
    -> carvernosa (paired) - dorsolateral
  • glans -> prepuse/foreskin
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30
Q

semen

A
  • 2-5ml
  • sperm: 50-150 million per ml
  • fluid from accessory glands
    • basic pH
    • fructose, nutrients & liquid to swim in
  • expulsion form urethra = ejaculation
    • peristaltic contraction of smooth muscles in ducts, glands, pelvic floor & base of penis
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31
Q

what regulates spermatogensis?

A
  • brain
  • puberty: GnRH stimulates release of LH and FSH from pit
  • LH tells leydig cell in testis to make testosterone
  • testosterone & FSH stimulate sertoli cell function -> supports developing germ cells
  • when spermatogenesis reaches sufficient levels sertoli cells produce inhibin to limit FSH production -> spermatogenesis decreases
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32
Q

endocrine disruptions in male reproduction

A
  • chemicals in environment can affect endocrine system & reproduction in utero
  • affects:
    -> structure of testis (-> fertility)
    -> structure of penis
    -> risk of testicular cancer
    -> testis descent
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33
Q

female reproductive system

A
  • internal and external organs
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34
Q

external organs in female reproductive system

A
  • clitoris
  • labia major
  • labia minor
  • vetsibular glands
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35
Q

internal female reproductive organs

A
  • ovaries
  • fallopian tubes
  • uterus
  • vagina
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36
Q

ovaries

A
  • produce gametes (oocytes)
  • produce hormones (endocrine)
  • paired
  • flattened ovoid
  • suspended in upper pelvis by ligaments
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37
Q

ligaments suspending the ovaries in upper pelvis

A
  • suspensory ligaments (to pelvic wall)
  • ovarian ligaments (to uterus)
  • both embedded within broad ligament
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38
Q

ovary histology

A
  • simple cuboidal germinal epithelium
  • tunica albuginea
  • stromal connective tissue (embedded with follicles)
    -> outer cortex
    -> inner medulla
  • follicles in cortex = oocytes & supporting cells
    -> produce hormones
    -> ovuum expelled each month
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39
Q

function of ovarian follicles

A
  • when an egg matures during a woman’s menstrual cycle, the follicle breaks open and releases the egg from the ovary for possible fertilization
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40
Q

atresia

A
  • oocytes undergo lots of degeneration
  • lose 1.5 million
  • only around 400 actually released after puberty
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41
Q

ovarian follicles

A

2 structures develop in female:
follicle/egg: oocyte/ovum + supporting tissue: follicle (follicular cells)

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42
Q

supporting cells in ovarian follicles

A
  • granulosa cells
  • theca cells
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43
Q

granulosa cells

A
  • epithelial: multi-layer as oocyte progresses through oogenesis
  • oestrogen synthesis
  • proliferate & multiply and become thicker as oocyte develops
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44
Q

theca cells

A
  • develop in secondary follicles
  • theca interna = androgen synthesis
  • theca externa = connective tissue
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45
Q

stages of oocyte development

A
  • pre-natal maturation: b4 birth -> generate primordial follicles
  • post-natal development: at puberty (monthly till menopause) -> some primordial follicles will undergo development and be released
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46
Q

what is oogenesis

A
  • production of the secondary oocyte
  • formation of female gametes
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47
Q

primordial follicles

A

primary oocyte + granulosa cells

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48
Q

process of oogenesis

A
  • puberty= several oocyte enlarge & granulosa cells divide -> primary follicle
  • fluid filled spaces form in granulosa cells -> become secondary follicles (still a primary oocyte!)
  • enlarges & fluid filled spaces form a single atrium -> mature / tertiary folcile (secondary oocyte)
    -> oocyte completes 1st meiotic division = secondary oocyte
  • secondary oocyte begins & doesnt complete the 2nd meiotic division
    -> at metaphse only completes division if fertilied by the sperm
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49
Q

why does a secondary oocyte only complete division if fertilied by the sperm

A

to preserve energy

50
Q

dominant follicle

A

only 1 secondary follicle will become mature for ovulation

51
Q

ovulation

A

= release of the secondary occyte (+zona pellucida) from ovary into peritoneal cavity

  • 2nd oocyte only completes 2nd meiosis at metaphase 2 is fertilised by sperm
  • many follicles mature each cyle but only one is ovulated
52
Q

corpus luteum

A
  • completely normal cyst that forms on the ovary every single month in women of childbearing age
  • a group of cells inside your ovaries that forms during each menstrual cycle
  • appears right after an egg leaves your ovary (ovulation)
  • enlarge and secrete hormones -> progesterone and estrogen fro 10 days
  • degenerates
53
Q

why are progesterone and estrogen secreted for 10 days?

A

to maintain the incase of uterine lining incase of pregancy

54
Q

corpus albicans

A
  • a scar on the surface of the ovary that is a remnant of ovulation
  • when corpus luteum degenerates
55
Q

PCOS

A
  • polycystic ovaries -> large number of harmless follicles
  • produce too much teststerone
  • many follicles develop but often not fully
  • cant release eggs -> no ovulation
  • hard to conceive
  • wieght gain
  • risk of diabetes and heart disease
56
Q

uterine (fallopian) tubes

A
  • paired
  • extends ovary - uterus
  • opens into peritoneal cavity
  • carries oocyte
  • expands at ovary = infundibulum
  • funnel shaped
  • long & thin
  • ampulla -> site of fertilisation
  • isthmus
  • lined by muscosa / mucous membrane
    -> simple columnar epithelium
    -> cilia to help move egg
  • muscularis -> smooth muscle
  • serosa -> serous membrane
57
Q

oocyte

A

female germ cell arrested in prophase of meiosis I

58
Q

how long does a fertilised egg travel

A

6 to 10 days

59
Q

ectopic pregnancy

A
  • implants outside uterus
  • life threatening
60
Q

uterus

A
  • womb
  • pear shaped
  • hollow muscular organ
  • site of embryo implantation
61
Q

3 sections of the uterus

A
  • fundus: large, rounded, post to fallopian tubes
  • body: central portion
  • cervix: inf, narrow, opens to vagina
62
Q

location of uterus

A
  • post to bladder, ant to rectum
  • leans foreward above bladder = anterverted
  • retroflexion: backward tipping -> can occur
63
Q

ligaments and pelvic floor muscles that support the uterus

A
  • broad= peritoneal fold from uterus lateral walls to wall of pevlis
  • round= extend through inguinal canals to labia majora, embedded in broad liagemnt
  • cardinal= lateral pelvic wall to attach on lateral cervix and vagina
  • utersacral= lateral wall of uterus to sacrum
64
Q

prolapsed uterus

A

if muscles weakend the uterus extends inferiorly into the vagina

65
Q

wall (layers) of the uterus

A
  • perimetrium = peritoneum serous membrane covering uterus
  • myometrium = thick smooth muscle layer, forms bulk of uterus
    -> cervical has less muscle, more dense connective tissue so rigid & less contractile
  • endometrium = mucous membrane - simple columnar epith. & lamina propria
    -> contains uterine glands and blood vessels
    -> functional zone thicker but undergoes changes during menstruation
    -> basilar zone: proliferates and replaces the functional layer in the next menstrual cycle
66
Q

uterine wall histology

A
  • during cylce can be 8mm thick
  • during menstruation most of endometrium lost
  • after 1mm thick
  • thick wall needed for embryo implantation
67
Q

cervix

A
  • neck of uterus - inferior
  • connects to vagina
  • columnar & squamous epithelial cells
  • protects reproductive system since open to outside world -> pathogens etc
68
Q

cervical mucous glands

A
  • physical barrier to substances from the vagina
  • needs to let sperm pass
  • near ovulation, mucous consistency changes
    -> gets thinner to allow sperm to enter and ovulate an egg
    -> if sperm binds -> mucous thicker
69
Q

cervical cancer

A
  • epitheliual change to squamous cells at certain times e.g. menstrual cycle
  • abnormal changes in cell shape -> visible early in cervical cancer
  • pap smear
70
Q

vagina

A
  • fibromuscular tube
  • gateway to uterus
  • pH acidic (protection)
  • passage for menstrual flow
  • birth canal
71
Q

wall layers of vagina

A

inner mucosa= stratified squamous epith.
- protection & lubrication in intercourse
- folded in rugae

hymen = mucous membrane covering vaginal oriffice

muscularis = inner longitundal & outer circular
- allows vagina to enlarge during childbirth & intercourse

adventitia = outer loose CT, anchors vagina

72
Q

vulva

A
  • female external genitalia
  • vestibular space
    -> urethral & vaginal openings
    -> mucous glands
    -> labia minora skin fold borders
    -> clitoris: erectile structure
  • labia majora:
    -> rounded folds of skin and fat
    -> medial surfaces sebaceous & sweat glands
    -> unite to form mons pubis ant
73
Q

female endocrinology

A

puberty leads to increased release of GnRH

74
Q

the senses

A
  • smell
  • taste
  • vision
  • hearing
  • balace
75
Q

general senses = somatosensation

A
  • touch
  • temperature
  • nociception (pain)
  • prorioception
76
Q

special senses

A
  • vision
  • hearing
  • balance & body position
  • olfaction (smell)
  • gustation (taste)
77
Q

sensory pathways

A
  • provides CNS with representation of external world

ascending-stimulus driven mechanisms:
stimulus -> sensory receptor (transducer) -> afferent sensory neurons -> CNS -> integration, perception

descending-goal directed mechanisms:
CNS-> descending neurons -> sensory receptor (tranducer)
e.g. movement away from stimulus

78
Q

sensation

A

detection of stimulus and recognition that an event has occured

79
Q

perception

A

interpretation and appreciation of that event

80
Q

how can sensory receptors vary?

A

by modality:

  • chemoreceptors
  • thermoreceptors
  • nociceptors
  • mechanreceptors
  • photoreceptors

by distribution:

  • general senses (somatosensory) -> widely distributed
  • special senses -> limited to the head

by stimuli origin:

  • interoceptors = detect internal stimuli
  • proprioceptors = position & movements of the body
  • exteroceptors =stimuli external to body
81
Q

sensory receptors

A
  • transducers -> convert stimuli into receptor potentials (opening of ion-gated channels)
  • produce graded potentials
  • transmit voltage changes into ganglion cells and discharge action potentials sent to spinal cord or brain
  • neural coding
82
Q

graded potential

A
  • need summation of small graded potentials to reach threshold and become an action potential
  • magnitude of receptor pot varies with stimulus strength
83
Q

neural coding

A
  • stimulus intensity encoded by number of receptors activated and the rate of APs
  • stimulus encoded by duration of APs in sensory neurons
  • the study of information processing by neurons
84
Q

what are sensory receptors?

A
  • free nerve endings
  • somatosensory, auditory or visual
  • little receptor specificity
  • synpase directly or indirectly on ganglion cells
85
Q

central pathways

A
  • axons in each sensory system (not olfactory or gustative) decussate and cross the midline
  • thalamus acts as a sensory relay
  • there is a specific nuclei and region for each sensory system in the thalamus
  • projections of thalamus into specialised cortical areas
86
Q

sensory cortex

A
  • over-representation of mouth, tongue and tip of index finger
  • fovea has large part of primary visual cortex
87
Q

what detects the sense of taste and smell?

A

chemoreceptors

88
Q

what detects the sense of hearing and equilibrium?

A

mechanoreceptors

89
Q

what detects the sense of vision?

A

photoreceptors

90
Q

special senses receptors

A
  • require special sensory receptors within large sensory organs located in head
  • e.g. ear & eye
91
Q

general senses receptors

A
  • receptors widely distributed in the body
92
Q

what is olfaction (smell) & gustation (taste)?

A
  • 2 chemical senses
  • chemoreceptors
  • special sensory receptors = chem receptors stimulated by chemical molecules (odorants)
  • complementary functions
93
Q

sense of smell

A
  • olfactory sensory receptors = bipolar neurons
  • olfactory epith = supporting cells, basal cells & olfactory receptor cells
  • axons synapse with ipsilateral olfactory bulb
  • cilia detect odorants
94
Q

olfactory transduction

A
  1. odorant molecules bind to receptor (G) protein on cilia
  2. depolarisation of olfactory receptor cells
  3. threshold reached -> APs sent to olfactory bulb
  4. in glomerulosa -> receptor nerve ending excite mitral cells -> send signal to primary olfactory cortex
  5. olfactory neurons form olfactory nerve (cranial nerve I)
95
Q

central pathway sense of smell

A

from olfactory tract -> pirmary olfactory cortex

96
Q

what is included in the primary olfactory cortex?

A
  • piriform (PIR)
  • enthorinal cortex (EC)
  • amygdala

PIR and EC form part of limbic system

97
Q

limbic system

A

hippocampus = memory
amygdala-hypothalamus = emotions

98
Q

orbitofrontal cortex

A

connects olfactory with gustatory

99
Q

sense of taste

A
  • taste buds in gustative papillae
  • taste buds = taste receptor cells = special neurons with membrane receptors sensitive to chemical molecules of diff shapes and ion charges
  • taste bud has 50-150 receptor cells
  • taste receptors have microvilli that extend through a pore -> microvilli exposed to surface saliva
  • each receptor cells specific to a taste
  • tasteants bind to respective stimuli and excite specialised neurons
100
Q

vision

A

light converted to neural signals in retina
photoreceptors

101
Q

retina

A

thin layer of cells on inner surface of back of eye

102
Q

photoreceptors

A
  • rods and cones contain photopigments
  • rods = night vision
  • cones = colour vision -> S cones, M cones, L cones
  • hyperpolarised by light
103
Q

retinal processing

A

3 neuron chain in retina
photoreceptor -> bipolar cells -> retinal ganglion cells

104
Q

what do retinal ganglion cells form?

A
  • only neurons that send APs along their axons
  • form the optic nerve
105
Q

where do the axons from the retina project to?

A

axons from retina project to:

  • primary visual cortex
  • superior colliculus
  • suprechiasmatic nucleus
106
Q

sense of hearing

A
  • outer, middle and inner ear
  • inner ear= uses mechanoreceptors = hair cells detect stimuli for hearing and equilibirum -> send neural signals to brain through vestibulocochlear nerve (cn VIII)
107
Q

middle ear

A

sound waves hit tympanic membrane -> auditory ossicles vibrate -> amplification of sound waves

108
Q

hair cells = auditory receptors

A
  • cochlea filled with fluid & contains hair cells
  • hair cells transduct mechanical waves into electrical signals
  • organ or corti = on top of basilar membrane, has hair cells, supporting cells & overyling tectorial membrane
  • hair cells have stereocilia on tips embedded in tectorial membrane
109
Q

sound transduction

A
  • sound waves travel to tympanic membrane -> vibrates
  • auditory ossciles conduct vibration into inner ear
  • movement of oval window -> pressue to perilymph
  • pressure waves distort basilar membrane
  • hair cells pushed against tectorial membrane
  • stereocilia bend
  • dischange AP
110
Q

basilar membrane

A
  • mechanical sound analyser
  • diff regions vibrate depending on sound wave frequency
111
Q

sense of equilibrium (vestibular)

A
  • inner ear encondes info on sense of balance
  • mechanoreceptor = hair cell with stereocilia = senses head pos, movement and if body in motion
  • head pos = sensed by utricule & saccule
  • head movement = sensed by semicircular canals
  • vestibulocochlear nerve -> info to brain stem & cerebellum
  • make up vestibular system
112
Q

vestibular system

A

provides the sense of balance and the information about body position that allows rapid compensatory movements in response to both self-induced and externally generated forces

113
Q

saccule and utricle.

A
  • respond to acceleration in a straight line
114
Q

seminiferous tubules

A
  • site of spermatogenesis in male testes
115
Q

The spongy urethra is largely lined with pseudostratified columnar epithelium, except the distal end which is lined with stratified squamous epithelium. Why might the distal end of the urethra be lined with this type of epithelium?

A
  • stratified squamous epithelium is composed of many layers of cells
  • protective function
  • distal end: at opening
116
Q

ovum

A
  • a fertilised egg
  • will travel along the uterine tube till it reaches the end of the uterus for implantation
  • if ovum does not reach uterus it can implant in uterine tube
  • called ectopic pregnancy -> rarely viable for developing fetus
117
Q

which region of the visual pathway is likely to be damaged if a patient is experiencing peripheral vision loss. Explain your reasoning.

A
  • damage in their optic chiasm
  • would inturrupt transfer of their visual info coming from medial visual fields -> would be unable to cross over the optic chiasm to the contraleteral optic tract
    -> loss of peripheral vision
118
Q

What structure in the ear is affected by roller-coaster rides? Why do you continue to feel disoriented even after the ride has stopped?

A
  • semicircular canals -> balance and equilibrium
  • fast spinning = canals detect directional balance and takes a minite for them to function normally again since the fluids will continue to spin
  • continuous spinning will cause the hairs to generate nerve impulses telling body you are still moving even if you are stationary
119
Q

Define what is meant by the “Hayflick Limit”. Why does this not apply to all stem cells?

A
  • due to reduced telomere length each mitotic cycle some cells can only divide a finite number of times
  • this limit = that finite number
  • not applied to all stem cells because many can reproduce indefinitely -> necessary for many biological systems
120
Q

Stem cells are required in areas where cells need to be replaced but they themselves cannot divide or differentiate. Give 2 examples of areas, similar to the situation described above, where you would find adult stem cells.

A
  • hair -> hair follicle stem cells
  • epithelium of intestinal system -> intestinal stem cells

human biology (11 decks)

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