worksheet answers Flashcards
(173 cards)
1
Q
What is the reason for having a very convoluted brain, i.e. many sulci and gyri?
A
Larger surface area means a greater volume of grey matter, which in the cerebrum consists of
billions of interneurons
2
Q
. Describe the distribution of white and grey matter in the different brain areas, including the
spinal cord. What do they represent?
A
Cerebrum: grey matter on the outside (cortex), white matter more internal (tracts connecting
different brain areas)
Midbrain, pons and medulla: Mostly white matter (various tracts, e.g. pyramidal tracts) with some nuclei (grey matter)
Spinal cord: “Butterfly” structure of grey matter in the centre with anterior (motor neuron cell
bodies) and posterior horns (sensory neuron cell bodies) and interneurons; white matter around
(motor and sensory tracts)
3
Q
What are the layers of the meninges? What are the subdural and subarachnoid spaces?
A
Dura mater = periosteal and meningeal layer, contains venous sinuses
Arachnoid = very fine connective tissue with fibres anchoring to pia mater
Pia mater = follows all the gyri into sulci
Subdural space = between dura and arachnoid, filled with fluid
Subarachnoid space = between arachnoid and pia, contains larger arteries and veins
4
Q
areas of cerebral hemisphere
A
Primary motor cortex
(precentral gyrus)
Primary sensory cortex
(postcentral gyrus)
Primary visual cortex
Broca’s area
Wernicke’s area
Prefrontal cortex
5
Q
Primary motor cortex
precentral gyrus
A
Large motor neurons (pyramidal cells); voluntary
muscle movement
6
Q
Wernicke’ area
A
Understanding written and spoken language
7
Q
Primary visual cortex
A
Interprets visual stimuli
8
Q
Primary sensory cortex
postcentral gyrus
A
Receives information from somatic receptors in the
skin and proprioceptors
9
Q
brocas area
A
Motor speech area, directs muscles that are
involved in speaking, also active when we think
about what we want to say
10
Q
Prefrontal cortex
A
Intellect, personality, working memory, abstract
thinking
11
Q
basal nuclei
A
Grey matter deep within cerebrum; involved in
motor function in coordination with substantia nigra
and cerebellum
12
Q
corpus callosum
A
White matter; tracts connecting both hemispheres
13
Q
areas of the diencephalon
A
Thalamus
Hypothalamus
Pituitary gland
Pineal gland
14
Q
thalamus
A
Relay station for all information coming into the
cortex; sorted, edited and integrated
15
Q
hypothalamus
A
Regulates homeostasis (temp, sleep, food, etc.)
16
Q
pituitary gland
A
Releases hormones to control endocrine system
17
Q
pineal gland
A
Secretes melatonin which induces sleep
18
Q
areas of the brainsem
A
Midbrain with
substantia nigra
Pons
Medulla oblongata and
pyramids
19
Q
midbrain and substantia nigra
A
White matter (pyramidal tracts) and some nuclei,
e.g. substantia nigra; involved in reflexes (startle
and visual) and RAS; substantia nigra produces
dopamine; exit point of cranial nerves
Note: RAS = reticular activation system
20
Q
medulla oblongata and pyramids
A
Top part of spinal cord; white matter (pyramidal
tracts in the pyramids); nuclei that are part of RAS;
cardiovascular and respiratory control; vomiting
and swallowing centre; sneeze and cough
reflexes; exit point of cranial nerves
21
Q
pons
A
White matter, some nuclei, respiratory control, exit
point of cranial nerves
22
Q
.When you feel tired during a long drive, you could open the window, sing along with the radio,
pinch yourself and have some cold water. How does this affect your alertness?
A
Increasing the amount of sensory input will activate the RAS (reticular activation system). The
more different stimuli that will be processed in various brain regions, the more effective this is.
Here you have skin sensation from the open window (wind and cold), auditory stimuli (music) and
activated taste receptors (cold water).
However, sleep can override the RAS, particularly if you are sleep deprived, so this is not always
working.
23
Q
Explain how cerebrospinal fluid is formed and describe its movement
A
Made by filtration in choroid plexuses in the ventricles; circulates through ventricles and in
subarachnoid space; lateral ventricles → third ventricle → fourth ventricle → through apertures
into subarachnoid space and also into central canal along the spinal cord
24
Q
- What channels in the presynaptic neuron open up in response to an action potential?
A
Voltage-gated Ca2+ channels
25
The presence of what ion inside the cell causes the synaptic vesicles to fuse with the
membrane?
Ca2+
26
Name six common neurotransmitters and whether they are excitatory or inhibitory
Acetylcholine (Ach) – can be both, very common in CNS and PNS
Noradrenaline – can be both, also in CNS and PNS
Dopamine – both, substantia nigra and other areas of CNS (“feel good” neurotransmitter
Serotonin – inhibitory, CNS (plays a role in mood, appetite, sleep)
GABA – main inhibitory, in CNS
Glutamate – main excitatory, in CNS
27
Describe the release and action of neurotransmitters
Neurotransmitters are stored in vesicles in the axon terminals. Ca2+ entering the axon due to an
AP causes the vesicles to fuse with the presynaptic cell membrane and release them into the
synaptic cleft.
They diffuse across and bind to receptors at the postsynaptic cell membrane. This triggers a
graded potential which can either lead to or prevent an AP.
28
How are neurotransmitters removed from the synaptic cleft?
They can be pumped back into presynaptic terminals (e.g. serotonin), broken down by enzymes
(e.g. Ach) or diffuse away.
29
Name three factors that can enhance transfer of information from short-term into long-term
memory
Practice and rehearsing
Being excited about the new information/task and having positive feelings
Being able to associate new information with previously learned facts and skills
Sleep enhances memory consolidation
30
Describe the stages of sleep and the order in which you progress through them during a
typical night. You can also draw this if you want.
REM sleep = rapid eye movement, often coincides with dreaming, high brain activity and muscles
paralysed
Non-REM stages 3 and 4 are deep sleep, showing delta waves
31
Where is the limbic system located and what is its role?
Various brain parts are involved, especially deep cerebral areas and parts of the diencephalon,
e.g. hippocampus, amygdala and other nuclei. This functional system regulates emotional
behaviour, such as reaction to stress or threats, aggression, etc. It is closely linked to the
olfactory (smell) areas.
32
When would you see delta waves, when alpha waves?
```
Delta = during deep sleep
Alpha = quietly alert, relaxed with eyes closed
```
33
. Describe the pathway for a sensory (afferent) stimulus from the receptor to the primary
sensory cortex.
First order neuron: Receptor = mechano-, thermo-, photo-, chemoreceptors or nociceptor →
distal branch of sensory neuron via peripheral and then spinal nerve (cell body is in dorsal root
ganglion) → proximal branch of neuron via dorsal root into dorsal horn
Second order neuron: Interneuron in dorsal horn → crosses over to the opposite side and axon
goes all the way to thalamus
Third order neuron: Cell body in thalamus → primary sensory cortex and other higher centres
(photoreceptor would send information to primary visual centre)
34
Describe the motor (efferent) pathway from the primary motor cortex to a muscle fibre
Upper motor neuron: Cell bodies in primary motor area (pyramid cells) → most axons cross over
to opposite side in medulla and go down spinal cord
Lower motor neuron: Cell body ventral horn → ventral root into spinal nerve → peripheral nerve
(and often via a plexus) → muscle fibre
35
general structure of a nerve
```
Nerve is surrounded by epineurium, contains fascicles (within perineurium) which are made up of
myelinated axons (encased in endoneurium). Nerves also contain blood vessels.
```
36
typical acending tract function
```
Sensory, i.e. pressure, touch,
temperature, pain, etc.
Afferent, i.e. transmitting
stimuli from the periphery and
internal organs to the CNS
```
37
typical acending tract number of neurons in the pathway
Three (first, second and third
| order)
38
typical acending tract origin
Receptors (distal branch of
first order neuron, cell body in
dorsal root ganglion) on body
surface, muscles or in organs
39
typical acending tract termination
Primary sensory cortex, some
| in cerebellum
40
typical acending tract where does it cross over (decussate)
Spinal level, i.e. same level
where first order neuron
enters the spinal cord
41
typical decending tract function
```
Motor, both skeletal and smooth
muscle fibres
Efferent, i.e. sending impulses
from CNS to skeletal muscles,
smooth muscles in organs and
blood vessels
```
42
typical decending tract number of neurons in the pathway
Two (upper and lower)
43
typical decending tract origin
Primary motor cortex in precentral gyrus, basal nuclei and
| cerebellum
44
typical decending tract termination
Neuromuscular junction or
synapses on smooth muscle
fibres
45
typical decending tract where does it cross over (dessucate)
In medulla, but some tracts
| don’t cross over
46
typical decending tract examples of tracts
Pyramidal, extrapyramidal
47
DRAW DIAGRAM OF REFLEX ARC
DRAW DIAGRAM OF REFLEX ARC
48
Neuropathic pain could have several reasons. Explain a reason
A decreased threshold for action potential generation in pain neurons.
(If the threshold OF -55 is decreased, a weaker stimulus will generate an action potential and get
perceived as pain.)
49
Explain the phenomenon of referred pain.
Visceral nociceptor get triggered by painful stimuli in the internal organs. Often these stimuli are
due to insufficient blood supply to that organ, causing ischaemia. Their fibres are bundled
together with fibres from pain receptors of specific skin areas and travel the same pathways to
the same regions in the CNS where the pain is perceived. The brain can’t quite distinguish where
the stimulus came from – organ or skin so it is felt in both areas.
Example: Pain in the left arm and jaw during a myocardial infarction
50
6. Which neurotransmitters and nerve fibres are involved in pain sensation?
Sharp pain – A fibres, burning and dull pain – C fibres
Neurotransmitters: Glutamate, substance P – they trigger second order neurons
These can be inhibited by the body’s own analgesia, i.e. endorphins and enkephalins
51
What is the difference between pain threshold and tolerance?
Threshold = the intensity of a stimulus that will be perceived as pain (not just pressure or
temperature). This is the same for every person
Tolerance = how pain is interpreted, perceived and tolerated. This varies from person to person and also
in different situations
52
Identify the 3 major roles of the ANS in relation to maintaining homeostasis
Cardiac regulation
• Secretory gland regulation (e.g. salivary, sweat, gastric, bronchial)
• Smooth muscle regulation (e.g. bronchi, blood vessels, GIT, urogenital)
53
There are no sympathetic neurons in the cervical spinal segments, yet there are three
cervical ganglia in the neck region. How can that be explained?
The preganglionic sympathetic fibers originate in the thoracic and lumbar segments of the spinal
cord. Some of these fibers ascend in the sympathetic trunk and synapse in three ganglia located
in the neck region (see figure 14.7)
54
Describe the meaning and importance of sympathetic and parasympathetic tone
“Tone” in the divisions of the ANS refers to the firing rate of sympathetic and parasympathetic
neurons. Sympathetic tone determines the degree of constriction or dilation throughout the
vascular system under resting conditions, while parasympathetic tone is important to determining
heart rate and GI function. The resting tone of each system aids in the maintenance of
homeostasis under normal conditions.
Sympathetic = vasomotor tone = slight vasoconstriction of arterioles during rest
Parasympathetic tone = vagus nerve keeps HR at 60-80
55
sympathetic NS origin
Thoraco-lumbar
Nerve cell bodies in lateral horns
T1-L2
56
sympathetic NS location of glangia
Alongside the spinal column –
| sympathetic trunk ganglia
57
sympathetic NS length of pre and post ganglionic fibres
Short pre
| Long post
58
sympathetic NS neurotransmitters and receptors
```
Preganglionic – ACh → nicotinic
Postganglionic – NE → α, β
Except to sweat glands – ACh →
muscarinic
Adrenal glands release
adrenaline and noradrenaline →
α, β
```
59
sympathetic NS functions
```
↑ mental alertness
↑ metabolism
↓ digestion & urine output
↑ respiration & dilate airways
↑ heart rate & blood pressure
activate sweat glands
control blood vessels
```
60
para sympathetic origin
Cranio-sacral
Cell bodies in some cranial nerve
nuclei, grey matter of S2-S4
61
para sympathetic location of ganglia
Close to or within the effector organs
62
para sympathetic length of pre and post ganglionic fibres
Long pre
| Short post
63
para sympathetic neurotransmitters and receptors
Preganglionic – ACh → nicotinic
Postganglionic – ACh →
muscarinic
64
para sympathetic function
```
↓ metabolism
↑ salivary & digestive
constrict airways
↓ heart rate & blood pressure
↑ gut motility & blood flow
↑ urine output & defecation
```
65
why might a person not have reflexes
Jimmy is in spinal shock. This is a transient period that follows the injury and can last for several
weeks. During spinal shock, there are no reflexes, flaccid paralysis below the affected level and
no sensation.
66
major nerves between c1 and 4
phrenic
67
major nerves between c5 and t1
brachial
| axillary, musculocutaneous, median, radial, ulnar
68
major nerves between l1 and l4
femoral, obturator
69
major nerves between l4 and s4
sciartic (tibial and common fibular
70
how the somatic and the autonomous NS
| work together
...
71
what is a dermatome
A dermatome is the area of the skin of the human anatomy that is mainly supplied by branches of a single spinal sensory nerve root
72
KNOW EYE DIAGRAM
EYE DIAGRAM
73
What is the blind spot and why is it blind?
The blind spot of the eye is the optic disc. This is the part of the retina where the optic nerve
(cranial nerve II) exits, so there are no photoreceptors. The brain fills in those blanks.
74
path that the information takes to the brain FROM RETINA
FROM PHOTORECEPTORS BACKWARDS TO AXONS OF GANGLION CELLS
75
Which sequence follows the correct passage of light entering the cornea?
cornea, anterior segment, pupil, lens, posterior segment
76
TYPE OF VISION THAT RODS ACCOMIDATE
Non-colour vision in dim light
77
TYPE OF VISION THAT CONES ACCOMIDATE
Colour vision in bright light
78
RODS PHOTO RECEPTOR SENSITIVITY
Very sensitive, i.e. require not
| much light
79
CONES PHOTO RECEPTOR SENSITIVITY
Low, require bright light
80
RODS LOCATION
Mostly in the peripheral retina,
| more numerous than cones
81
CONES LOCATIONS
Central retina
82
Which part of the visual field would be affected by a tumor in the right visual cortex and by a
tumor compressing the right optic nerve?
A tumour in the right visual cortex would affect the whole left visual field. If the right optic nerve is
compressed, parts of the left and right visual fields from the right eye would be affected
83
GLAUCOMA
A problem with the drainage of the aqueous humour (= fluid in the anterior segment
of the eye) increases the amount of this fluid and therefore the pressure in the whole eye (normal
= 16mmHg). This compresses the retina and optic nerve which can eventually lead to blindness
84
CATARACT
A clouding of the lens, mostly due to age-related thickening and hardening. It leads to
blurred vision. Risk factors are smoking and diabetes.
85
Where do you find taste buds?
On all parts of the tongue and some on the palate, cheeks, epiglottis and pharynx
86
Name some characteristics of olfactory receptor cells
They are chemoreceptors, are bipolar neurons, have cilia, have a short life-span (30-60 days)
and get replaced.
87
Name the five taste modalities and examples of chemicals that trigger them.
```
Sweet: sugars, alcohol, amino acids
• Sour: acids, H+
ions
• Salty: metal ions, salt
• Bitter: alkaloids, e.g. caffeine
• Umami: glutamate
```
88
Why can smell trigger an emotional response? Explain this by listing the sequence of the
olfactory pathway from receptor to the brain.
Olfactory receptors → olfactory bulb → olfactory tracts → cranial nerve I (olfactory) → primary
olfactory cortex (temporal lobe) → two pathways: 1) to the frontal lobe for further interpretation and
2) to the limbic system, which is the emotional centre of the brain. Dangerous smells can trigger a
flight and fight response, appetising smells activate the digestive system via the ANS. However,
many smells just elicit emotional responses and/or memories.
89
KNOW EAR DIAGRAM
KNOW EAR DIAGRAM
90
Define transduction using the example of hearing.
Transduction = the stimulus energy gets converted into a graded potential. In the case of the
receptor being a separate cell (so not the peripheral axon of a sensory unipolar neuron), this is
called a receptor potential. The receptor potential leads to the release of neurotransmitters from
the receptor cell.
In the case of the ear, sound waves make the basilar membrane vibrate, which stimulates the
cochlear hair cells and their stereocilia as they move and pivot with that vibration. This opens ion
channels causing a graded receptor potential in the cochlear hair cells.
91
Define transmission using the example of hearing.
Transmission = passing on of the receptor potential as APs along sensory (afferent) neurons and
nerves.
In the ear, the receptor potential in the cochlear hair cells causes the release of
neurotransmitters (glutamate) from those cells which causes depolarisation and APs in the
sensory neurons and their axons that eventually form the cochlear nerve.
92
2.How do we hear sound? Describe the structures involved from sound waves to brain
Sound waves travel through the external meatus, hit the tympanic membrane and make it vibrate
→ auditory ossicles pick up, amplify and transfer the vibration to the oval window → triggers
movement of perilymph and endolymph in the cochlea → the spiral organs in the cochlea contain
cochlear hair cells (see Q 10, 11) → cochlear nerve → cranial nerve VIII (vestibulocochlear) →
midbrain → thalamus → primary auditory cortex (temporal lobe)
93
How are sound waves characterised and how does that relate to sound interpretation? Name
the units that are used for measuring the two characteristics.
```
Frequency = pitch, measured
in Hertz (Hz)
Amplitude = loudness,
measured in decibels (dB)
```
94
structure in inner ear that is responsible for hearing
cochlea and cochlear hair cells
| in the spiral organs
95
.Define nystagmus.
Sudden, jerking eye movements that occur during and immediately after rotation of the head
and/or body.
96
Major areas of the ear
External, middle and inner ear. Inner ear (labyrinth) is comprised of cochlea and vestibular
apparatus (= vestibule and semicircular canals)
97
which parts OF EAR are responsible for hearing and for balance,
The inner ear (also called the labyrinth) contains 2 main structures — the cochlea, which is involved in hearing,
the vestibular system (consisting of the 3 semicircular canals, saccule and utricle), which is responsible for maintaining balance.
98
What are the three main sources of sensory input that the brain uses in order to control
balance and equilibrium?
Vestibular receptors of the labyrinth (maculae in the vestibule and cristae ampullares of
semilunar canals); visual receptors (rods and cones) and proprioceptors of muscles, tendons and
ligaments (see figure 15.36)
99
endocrine hormone diagram
endocrine hormone diagram
100
define Paracrine and autocrine
Paracrine hormones travel only a short distance and act on close by cells in the same tissue.
Autocrine hormones are released into the extracellular fluid by the same cell that they act on.
101
define Steroid- and amino acid-based hormones (provide some examples)
Steroid based hormones derive from cholesterol, are not water soluble, have a long half-life
and can cross the plasma membrane. They travel in the blood stream bound to plasma proteins. They act directly on the genetic material of the cell and trigger the production of
specific substances. Examples: Sex hormones and cortisol.
Amino-acid based hormones are manufactured from amino acids, are water soluble and
therefore cannot cross the plasma membrane of cells. They have to bind to specific receptors
on the target cell membranes to have an effect on them (via second messengers). They are
short-lived and travel freely in the blood. Example: Growth hormone (GH), ADH, LH, FSH, etc.
102
define Pineal gland
Small gland in the epithalamus region that produces and secretes melatonin which regulates
sleep onset.
103
Discuss how hormone release is regulated and what determines their activity.
• Hormones are released
➢ in response to an alteration in the cellular environment
➢ to maintain a regulated level of certain substances or other hormones
• Release has patterns – diurnal, cyclic
• Hormones are regulated by chemical or humoral (e.g. calcium levels), endocrine (e.g. TSH,
FSH) or neural (e.g. sympathetic NS) factors
• Negative and positive feedback cycles
• Up and down regulation – increased or decreased number of receptors depending on
hormone levels, e.g. (↓ hormone → ↑ receptors per cell
• Half life = hormone’s blood level decreased to half of the original concentration that was
released from the gland
➢ Inactivated by enzymes
➢ Removed by kidneys or liver and excreted in urine or faeces
104
How do hormones interact?
Permissiveness = hormone can only have full effect if another hormone is present, e.g.
thyroxin and action of sex hormones in puberty
• Synergism = two hormones have the same effect on target cell, e.g. glucagon and
adrenaline ↑ BSL
• Antagonism = hormones that have opposite effect to each other, e.g. glucagon (↑ BSL) and
insulin (↓ BSL)
105
nervous system vs endocrine system response speed
NS- rapid
| E- slowly
106
NS vs E duration of response
N- short duration
| E- long duration
107
NS vs E mode of action
N- action potentials and neurotransmitters
| E- Hormones in the bloodstrea
108
NS vs E act at what location
NS- act at specific locations determined by axon pathway
| E- acts at diffuse locations - targets anywhere blood reaches
109
NS v E how localised is response
NS- neurotransmitters act over very short distances
| E- hormones act over long distances
110
. Describe the difference between the communication of the hypothalamus with the anterior
and the posterior gland. Use the examples of oxytocin and GnRH. What are the target cells
for these hormones and what is their effect?
pituitary gland where they are stored. APs from the hypothalamus sent down those axons cause
release of oxytocin from the posterior pituitary gland into the blood stream.
Action: Uterine contractions, milk ejection (let-down reflex)
```
GnRH: Also produced by hypothalamic neurons and released into capillary plexus to get to the
anterior pituitary gland where it binds to receptors on gonadotropic cells.
Action: GnRH stimulates gonadotropic cells to release follicle-stimulating hormone (FSH) and
luteinising hormone (LH).
```
111
The anterior pituitary gland releases several hormones, examples
Growth hormone
(GH, somatotropin)
Adrenocorticotropic
hormone (ACTH)
Prolactin
Thyroid stimulating
hormone (TSH)
Follicle stimulating
hormone (FSH)
Luteinising hormone
(LH)
112
growth hormone target and effect
Liver, adipose tissue Stimulates bone & muscle growth,
promotes protein and fat synthesis, ↓
glucose uptake and metabolism
113
adrenocorticotropic hormone target and effect
Adrenal gland Stimulates synthesis and secretion of
| adrenal cortical hormones
114
prolactin target and effect
Uterus, breast Prepares the female breast for
| breastfeeding, effect in males unclear
115
thyroid stimulating hormone target and effect
Thyroid gland Stimulates synthesis and secretion of
| thyroid hormone
116
follicle stimulating hormone target and effect
Ovary, testes Ovarian follicle and ovulation in
females and sperm production in
males
117
luteinising hormone target and effect
Ovary, testes Development of corpus luteum,
release of oocyte, oestrogen,
progesterone, testosterone and testes
118
how the regulation of blood glucose levels is regulated.
| Include hormones, organs and processes in the liver. Where do the hormones get produced?
s- high
r- chemo receptors in beta cells
m- pancrease releases insulin
e- glycogen formation in liver, glucose uptake by cells
r- blood glucose falls
f- normal
119
what is insulin
➢ Produced and secreted by beta cells in the Islets of Langerhans
➢ Facilitates the rate of glucose uptake into the cells of the body to meet energy needs
of cell (ATP production!)
➢ Inhibits glycogenolysis and gluconeogenesis in the liver
➢ Synthesis of glycogen (in liver) and conversion into fat (in adipose tissue) if too much
glucose
120
what is glucagon
gon
➢ Produced and secreted by alpha cells
➢ Stimulates glycogenolysis, gluconeogenesis (in liver) and lipolysis (in adipose tissue)
121
Draw two flow charts/feedback cycles that illustrate both the short term and the long term
stress response. You need to include the ANS as well.
Draw two flow charts/feedback cycles that illustrate both the short term and the long term
stress response. You need to include the ANS as well.
122
Cardiovascular system long and short termn stress response
short- ↑HR, ↑BP, ↑CO
Vasoconstriction of peripheral
arterioles
long- increase BP due to ↑blood volume
Vasoconstriction (RAAS)
123
Respiratory system long and short term stress response
short-↑resps
bronchiodilation
long- nil
124
liver short and long term stress response
short- Glycogenolysis → ↑BSL
long- Gluconeogenesis (amino acids
and fatty acids)
125
skeletal muscle long and short term stress response
short- Increased blood flow
Glucose for fuel
long- Break down to produce amino
acids for liver to use
Use fatty acids for fuel
126
adipose tissue long and short term stress response
short- nil
long- Releases fatty acids into blood
127
kidneys long and short term response
short- ↓diuresis
long- Na+
reabsorption → H2O follows
→ ↑blood volume (aldosterone)
128
What is the role of the thyroid gland?
• Affects growth of tissues (nervous, musculoskeletal, reproductive) and development
(especially during childhood and puberty)
• Cell metabolism, determines basal metabolic rate
• Heat production
• Mood
• Skin – sebum production and hydration
• Cardiac function
• GIT – promotes gut motility and helps regulating digestive juices
129
hormones produced by thyroid
t3 and t4
130
What happens to the oocyte from ovulation to implantation? What enables the zygote to travel
from the uterine tube to the uterus?
• Secondary oocyte gets released into peritoneal cavity during ovulation.
• Uterine tubes drape over ovary, fimbriae stiffen, and cilia sweep oocyte into tube.
• Peristalsis of the tube and beating cilia transport the oocyte towards the uterus; mucosa
produces nourishing secretions.
• If fertilisation occurs, oocyte completes meiosis II and becomes a zygote.
131
2. What are the two main stages of human development in utero? (Include time frame and main
tasks)
Embryo = fertilisation to end of week 8; time of organogenesis
• Foetus = week 9 to birth; growth and maturation of organ systems
132
Describe the three stages of labour
Dilation:
a. Early – baby’s head engaged
b. Late – baby’s head rotates, cervix 10cm dilated
2. Expulsion – baby’s head extends as it is delivered
3. Placental – placenta detaches from uterus and is expelled
133
Gene
DNA sequence that carries information for creating proteins and non-coding
sequences
134
Allele
different versions of the same genes on the homologous chromosomes (paternal
and maternal version); expression can be the same or different
135
Meiosis
cell division of the gametes in order to have haploid sperms and oocytes;
causes genetic variability
136
Genotype
genetic make-up of a person, i.e. the different alleles for traits
137
Phenotype
expression of genes, i.e. how a trait manifests in the person
138
Homozygous
alleles for one trait on paternal and maternal chromosomes are the same
139
Heterozygous
alleles are different
140
Describe two mechanisms during meiosis that produce genetic variability
Crossing over = exchange of parts between homologous chromosomes during meiosis I,
leads to recombinant chromosomes
• Independent assortment = random distribution of paternal and maternal chromosomes into
daughter cells during meiosis I
141
In a marriage between 2 colour blind people, would all their children be colour blind?
yes
142
Define epigenetics.
Chemical changes to the genome that do not involve alterations to the code itself, so changes in
phenotype but not genotype. These can be inherited as well.
two main mechanisms: DNA methylation = silenced for transcription and DNA acetylation = available to be
read
143
. Discuss how epigenetics and the environment and their interaction can influence a person’s health.
The central dogma of genetics presumed that a person’s genetic make-up determined their health. With
the discovery of various regulatory mechanisms of the DNA sequences it is now apparent that those
mechanisms can override or influence the gene expression. Many of these mechanisms (epigenetic
markers, imprinting, mitochondrial DNA and non-coding RNAs) are affected by life-style choices,
especially nutrition and exposure to drugs or pathogens. As these can affect both sperms and oocytes,
these changes can be passed on to the next generations.
Many diseases are now thought to be triggered by the interaction of environmental and epigenetic factors,
e.g. cardiovascular diseases, obesity, diabetes, most cancers, bipolar disorder, schizophrenia, autism,
Alzheimer’s, Parkinson’s and autoimmune diseases.
If a person has a genetic pre-disposition, making healthy lifestyle choices can help prevent the onset of
the disease or at least delay it until older age.
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what are the different inheritrance types
autosomal dominant, recessive
x linked dominant, recessive
y linked
codominant
mitochondrial
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Why is genetic counselling important?
As some genetic tests may not provide all the information that families may want, the test may
subsequently require difficult decisions without providing full information, e.g. a couple who
knows their child is positive for cystic fibrosis, the ethical dilemma involves the decision to
continue or to end a pregnancy without having knowledge of the severity of the disorder.
Genetic testing for some conditions for which there are no treatments to date has the potential to
cause psychological harm, stigmatisation, and discrimination. Genetic testing for Huntington's
disease (HD), a progressive motor and cognitive disorder with onset in midlife, is one example.
Individuals who have an affected parent have a 50% chance of inheriting the gene mutation for
HD and have the option to pursue genetic testing. A person who has the HD mutation has a
100% chance of developing the disease. There are no effective treatments or preventive
measures currently available. Thus, choosing to have genetic testing for HD is highly personal,
and it is recommended that individuals considering HD testing have extensive pre-test
counselling. Although knowledge that one has the HD gene mutation helps some individuals with
reproductive and career planning, other individuals at risk for HD are concerned about the
psychological and potential discriminatory harms from testing.
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What is the difference between mitosis and meiosis?
To start off with it’s the same as in mitosis. Two homologous chromatids duplicate and produce
two homologous chromosomes. In meiosis they that snuggle up tightly and form a tetrad during
prophase I. In metaphase I they line up in the centre, like in mitosis. In anaphase I, however, the
chromosomes separate, and each cell only has a haploid set of chromosomes (still with two
chromatids). In meiosis II (which is basically like mitosis), these split into their chromatids which
end up in the two daughter cells.
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What is the outcome of meiosis?
* It reduces the chromosomal number to half (haploid)
| * It introduces genetic variability (cross-over)
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Gamete ?
specialised cells for reproduction, i.e. sperm and ovum
149
Gonad?
primary sex organs (testes and ovaries) that produce the gametes
150
Haploid?
number of chromosomes in gametes → contain 23 chromosomes (n)
151
Sister chromatid?
identical chromatids in a chromosome that is either paternal or maternal.
This replication of the DNA happens during interphase.
152
Diploid
number of chromosomes in body cells → contain 23 pairs of homologous
pairs/sets of chromosomes → 46 chromosomes (2n)
153
Describe the journey of sperm from the male testes to the uterine tube of a female
Testis, epididymis, ductus deferens, male urethra, vagina, cervix, uterus, uterine tube
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How is sperm adapted to fulfil its task of fertilisation?
They are produced in large numbers,
• Have a tail for movement,
• Have enzymes in the acrosome to digest the ovum lining before entry
• Receive nourishment from fluids of the accessory glands
• Are surrounded by that alkaline fluid to be protected from acidic environment in vagina
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What is the function of the testes?
Produce testosterone
| • Produce sperms
156
Draw a flowchart of hormone regulation for the male reproductive system – include the three
levels and effector organs
Draw a flowchart of hormone regulation for the male reproductive system – include the three
levels and effector organs
157
What are the effects of testosterone?
* Anabolic effects throughout body (↑ bone and muscle mass)
* ↑ metabolic rate,
* ↑ haematocrit),
* Mood
* Libido
* In puberty development of secondary sex characteristics (hair pattern, voice, thicker skin)
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The female reproductive organs
| • Use the models and label the diagram
The female reproductive organs
| • Use the models and label the diagram
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vagina function
Copulatory organ, passage for menstrual blood and
delivery, acidic pH (prevents infection), 3 layers
(adventitia, muscularis and mucosa)
160
ovaries function
Gonads, produce ova (eggs) and female hormones, held
in place by various ligaments (ovarian ligament), contain
follicles in various stages
161
uterine tube function
Also known as fallopian tubes, suspended from uterus to
peritoneal cavity via various ligaments, have fimbriae at
the end, located close to ovary, fertilisation happens here!
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uterus function
Hollow muscular organ, fundus at top, cervix at inferior
end, 3 layers, fertilised egg embeds, and embryo can
develop
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.List the layers of the uterus wall
Endometrium – the mucosal lining, produces the functional that allows the fertilised egg to implant
itself
Myometrium – smooth muscle, contracts rhythmically during childbirth
Perimetrium – outermost layer
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Define ovulation and describe how it is triggered
Ovulation is the rupturing of the vesicular follicle and the release of the secondary oocyte into the
peritoneal cavity. Ovulation takes place approximately on day 14 of the ovarian cycle and is
triggered by a surge in LH.
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What is the function of the ovaries?
Produce oestrogen and progesterone
| • Produce follicles and oocytes
166
define Follicle
envelope of cells around oocyte
167
define oocyte
gamete before it becomes proper ovum/egg (happens after fertilisation)
168
define corpus luteum
left over follicle after ovulation, becomes an endocrine gland as it
produces progesterone and oestrogen
169
define polar body
= small daughter cells after meiosis I and II of the secondary oocyte; die off
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4.When is the best time for conception and why?
Sperm can last several days in the female reproductive tract (especially the x ones) and the
secondary oocyte can live up to 24 hours after ovulation, so 48 hours prior to ovulation to 24
hours post ovulation is the best time.
171
5.Draw a flowchart of hormone regulation for the female reproductive system – include the
three levels and effector organs.
5.Draw a flowchart of hormone regulation for the female reproductive system – include the
three levels and effector organs.
172
briefly outline the phases of the ovarian and uterine cycles and the role of
the hormones.
Normal length of cycle is about 28 days.
Ovarian cycle: First half follicular = vesicular follicles secrete more and more oestrogen, of the
vesicular follicles becomes dominant; ovulation takes place on day 14 (positive feedback from
oestrogen causes LH surge); second half is luteal with corpus luteum producing mainly
progesterone and some oestrogen; negative feedback for FSH and LH
Uterine cycle: Menstrual phase first; then proliferative phase (day 5-14) where endometrium
starts to grow, thicken, lots of blood vessels (this can be longer than 14 days); then secretory
phase after ovulation where endometrial glands secrete nutrients, ready for a potentially fertilised
egg (always 14 days)
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The basic difference between spermatogenesis and oogenesis is that ________.
in oogenesis, one mature ovum is produced from the parent cell, and in spermatogenesis four mature sperm are produced from the parent cell
