Week 3 Flashcards
Where is the pelvic cavity found?
Within the bony pelvis between the pelvic inlet and outlet
Describe the peritoneum.
A thin transparent serous membrane that lines the abdominal cavity and drapes over the pelvic viscera.
What are the pouches created by peritoneum in females?
Vesico-uterine
Rectouterine (Pouch of Douglas)
Why is the rectouterine pouch clinically important?
In an upright female this is the lowest point of the abdominal cavity therefore excess fluid can gather here.
What is the pouch created by the peritoneum called in males?
Rectovesical
What are the primary and accessory organs of the female reproductive system?
Primary - Ovaries
Accessory - Uterine tubes, uterus, vagina.
Describe fimbriae.
Finger like projections that gather the egg when it is released into the cavity.
What are the 3 layers of the uterus?
Perimetrium
Myometrium
Endometrium
Where does fertilisation normally occur?
Ampulla
What is the most common position of the uterus?
Anteverted and anteflexed.
Where do ovaries and testes develop?
Posterior abdominal wall.
What arteries supply the female reproductive system?
Ovarian artery
Uterine artery
Internal iliac artery
What is the inguinal canal?
The route which the testes follow from the abdominal wall creating a tunnel.
What does the dartos muscle do?
A smooth muscle that moves the testes further from and closer to the body to control temperature
Describe the pathway of sperm cells.
Produced in the seminiferous tubule.
Pass into the rete testis.
Then into the head of epididymis which becomes the vas deferens
What are the primary and accessory organs of the male reproductive system?
Primary: Testes
Accessory: Vas deferens, seminal glands, prostate gland, penis.
What gland produces seminal fluid?
Seminal gland.
Where do the right and left ejaculatory ducts join?
Prostate gland.
When do the conceptus, embryonic and foetal period occur?
Conceptus - Weeks 0 - 3.
Embryonic - Weeks 3 -8.
Foetal - Weeks 9 - 40.
What are the 6 phases of embryogenesis?
Gametogenesis
Fertilisation
Cleavage
Gastrulation
Formulation of a body plan
Organogenesis
Describe male and female gametogenesis.
Female - Occurs in utero by weeks 28 - 30 when the gametes arrest in prophase. This is completed in puberty.
Male - Occurs at puberty and continues throughout life.
When do the majority of nondisjunction cases occur?
Oocyte formation
What is nondisjunction?
Incorrect separation of chromosomes in formation
Define polyspermy.
More than one sperm fertilise one egg.
Describe some mechanisms to prevent polyspermy.
The zona pellucida causes cortical granules to release their contents on penetration to render it impenetrable to others.
The zona pellucida depolarises.
What occurs during cleavage of the zygote?
Rapid mitotic division where individual cells get smaller and the structure remains the same size.
The morula then the blastocyst are formed.
What occurs during gastrulation?
The germ layers are formed and the body axis is established.
In what week are the germ layers of the embryo formed?
Week 3
What are the 3 germ layers of the embryo?
Ectoderm
Mesoderm
Endoderm
What does the yolk sac of the embryo become?
The gut tube
During what weeks does organogenesis occur?
4 to 8
Which period does most foetal growth occur in?
The foetal period
What is cell induction?
The ability of one cell type to cause another to differentiate either directly or at a distance.
Describe fertilisation.
Sperm binds with zona pellucida glycoprotein ZP3.
Acrosomal enzymes are released from the sperm head allowing it to digest its way into the egg.
Egg and sperm membranes fuse allowing the sperm entry.
Sperm entry triggers release of cortical granules.
What is the difference between a totipotent and a pluripotent cell?
Totipotent can differentiate to anything including any cell related to the embryo e.g. placenta.
Pluripotent can differentiate to any cell.
What type of cells surround an egg cell?
Follicle cells.
What are the daughter cells of a zygote called?
Blastomeres.
Describe the morula.
> 16 blastomeres.
Confined within the zona pellucida, outer cells form extensive gap junctions.
When does the blastocyst develop?
Days 4-5.
What does the trophoblast form and where is it found in the blastocyst?
Foetal part of the placenta.
Edge of the blastocyst.
What does the inner cell mass of the blastocyst form?
Embryo proper
What must occur to a blastocyst before implantation?
Burst through the zona pellucida through forceful contraction and release.
When does implantation normally occur?
Day 6
Where does implantation normally occur?
Most commonly posterior uterine wall but may be anterior.
What is the corpus luteum?
Forms within the ovary every month and releases progesterone. It degenerates if the egg is not fertilised.
When the bilaminar embryo forms what does the trophoblast divide into?
Cytotrophoblast
Synctiotrophoblast
What produces hCG in the bilaminar embryo?
Synctiotrophoblast
What are the 2 layers of the bilaminar embryo?
Epiblast
Hypoblast
When does the bilaminar embryo form?
Day 7
What is the function of the fibrin coagulum?
Plugs the defect in endometrial lining caused by implantation.
What cavities do the epiblast and hypoblast form?
Epiblast - Amniotic
Hypoblast - Primitive yok sac
What happens on day 12 in the bilaminar embryo?
Establishment of uteroplacental circulation.
Extraembryonic mesoderm develops and eventually degenerates forming the chorionic cavity.
What happens in day 13 in the bilaminar embryo?
Chorionic cavity development and connecting stalk development.
Second wave of hypoblast cells migrate to form the definitive yok sac.
The scynctiotrophoblast extends to form what?
Uteroplacental circulation
When is the primitive streak formed?
Week 3.
What does the primitive streak do?
Sets up the body axis.
What does the ectoderm develop into?
Epidermis of skin
Nervous system
What 3 regions does the mesoderm develop into?
Paraxial
Intermediate
Lateral plate (Somatic and visceral)
What is a notochord?
A flexible but rod like middle structure
What does the paraxial mesoderm develop into?
Axial skeleton
Skeletal muscle
Parts of dermis (back)
What does the intermediate mesoderm develop into?
Urogenital system (kidney, ureter, gonads and associated structures)
What does the somatic part of the lateral plate mesoderm develop into?
Most of the dermis
Lining of body wall
Parts of limbs
What does the visceral part of the lateral plate mesoderm develop into?
Cardiovascular system
Mesothelial covering of organs
Smooth muscle
What does the endoderm develop into?
Lining of the gut tube
Lining of the respiratory tract
Lining of the bladder and urethra
What is normal core body temperature?
37.8
Define normothermia
The narrow range core body temperature is maintained at to maintain optimum cellular function and metabolism
What can occur at too high a body temperature?
Protein denaturation, nerve malfunction, convulsions, death
What can occur at decreased body temperature?
Reduced cellular metabolism and function
What is the normal range for ear measured temperature?
36 - 37.5
What is an abnormally high body temperature (fever) and what is hyperthermia?
Fever: 38 - 40
Hyperthermia: >40
What temperature would be considered hypothermia?
<35
What is diurnal variation in body temperature?
Temperature varies slightly during the day
How can heat be lost to the external environment?
Radiation
Conduction
Convection
Evaporation
How can heat be gained from the external environment?
Radiation
Convection
Conduction
How can heat be gained from the internal environment?
Metabolic heat gain
What is the basal metabolic rate?
The minimum amount of energy required to sustain vital body functions, leading to basic heat production
What can increase the basal metabolic rate?
Hormones such as adrenaline, noradrenaline and thyroxine.
Muscle activity e.g. shivering.
What occurs during heat conduction?
Heat moves from a warmer to cooler object.
Depends on temperature gradient and thermal conductivity.
What occurs during convection?
Combines with conduction to dissipate heat from the body.
Transfer of heat energy by air or water currents.
Where is the temperature control centre?
Hypothalamus
What parts of the hypothalamus are activated by cold and hot?
Cold: Posterior hypothalamic centre.
Hot: Anterior hypothalamic centre.
What white cells are involved in resetting the temperature set point in fever?
Macrophages.
What do endogenous pyrogens do?
Stimulate the release of prostaglandins in the hypothalamus, resetting the temperature set point to a higher temperature in fever.
What is fascia?
A type of connective tissue that wraps the deep structures of the body.
What are the two basic types of fascia?
Deep
Superficial
Give some general functions of fascia.
Protective padding
Thermoregulation
Support for tissues and organs
Reduce friction
Transmit mechanical force
