A first glance in the mirror reveals to me a girl with a short straight bob of light brown hair, the tips of her ears poking out through the silky locks. Her smooth white skin is pockmarked in places, but is free of major blemishes. There appears to be a faint grey line along her jawline, as if she had accidentally painted herself with pigment leftover from a great work of art. Other than that, there isn’t any trace of makeup, except perhaps a hint of mascara on the sensuous long lashes hidden behind the fall of hair.

Her legs, hairless and smooth, protrude from too short army pants into a pair of worn grey sneakers. The soles of the shoes are starting to come apart, the tips of the toenails peeking out the end. The knees are slightly scabbed, as if the owner had fallen over recently. Perhaps she had been pushed without warning, because there are no corresponding marks on the palms of her hands as if she had tried to stop her fall.

Her upper body is hidden inside a baggy yellow and black shirt, which could equally hide as well as reveal. The writing says “No Pain, No Gain”, a strange choice for a girl that is otherwise very feminine. She longs to buy the beautiful pink lacey underwear, the supportive black bras and frilly corsets open to women. She wouldn’t worry about the associated sexual connotations, who would want her anyway? She isn’t interested in sex, or attracting someone else. She’d wear them just for herself, as a celebration of her body.

There is a glimpse of her long arms as the fabric shifts and this reveals that they too are shaven smooth, culminating in well-manicured fingernails that have a hint of shine from buffing. On one wrist there is a flat white scar, where the owner had cut herself the first time she tried to shave. Now she waxes, and the hair growth is slowed. The length of the nails is surprisingly short, as if the ends have been nibbled down in worry, yet the tips are perfectly curved. The half-moon whites are visible, delicately exposed from under the cuticles. Some of the fingers have ripped skin, hangnails, where blood has run down the sides of the nail, and there is dark blood under the fingertips.

The next glance gives me so much more insight into her. Under that fall of silken shiny smooth hair are eyes with grey shadows underneath them. The pale eyebrows have been plucked thinly, their points stretching out no further than the edges of the eye. Those eyes would haunt anyone who saw them, their bright blue startling against the framing eyebrows. There is a single earring too, tucked under another bit of hair. It is a diamond, a true diamond, that her father had bought for her in an effort to improve the quality of her appearance.

The body – now that’s a surprise to others, if they ever saw her naked. Instead of the gentle swell of breasts, there is a flat chest, waxed and hairless. The skin is pale, and the veins stand out clearly. Those veins are repeated on the inner arm, but there they are marred by white scars. The feet are another unusual feature. They are large, abnormally so for a woman, again with well-tended nails. There are scars here too, on the sole of the feet. Those scars are external proof of what happened to her, fleeing along a deserted stony path. Let me escape describing the genital area to you, perhaps you can already imagine what it is like. How crude of me even to suggest it.

The mirror shears off another layer. Just underneath the fragile skin is a boiling pool of worry and regrets. When the rape happened, they said she might have lost her penis because of the blood supply being cut off. She wishes it had been. It might be necessary for reconstructive surgery, but it’s an appendage she wouldn’t miss. She doesn’t think she could stand another having sex with her, so why bother with the painful process? She would have to constantly stretch the skin with that special device, constantly worrying that it will close up and be too small.

One of her favourite movies always was TransAmerica. Sure, it was corny and stupid, but sometimes the film makers get that uncertainty right. Perhaps she has fathered a child. How would she know? They never bothered to find who raped her. Who would rape a person like her? She was too strange for anyone to understand. They blamed her eventual transformation on the rape, but that wasn’t fair. She’d always been different.

Another layer: inside is just a child. The child that they didn’t realise or recognise that was different. They were purposefully blind to her plight. The traditional ‘stick their heads in the sand to make the problem go away’. If she’d had access to dolls and dresses, then she would have dressed up. She dreamed of being a princess not a monster. As a male, she always got extra attention at school because she was too soft. She cried when others pushed her. What sort of child does that? A normal child, a happy child, wouldn’t have. She was consistently confused for which bathroom to use. The one with the woman in the dress she could identify with, not the ramrod straight black man.

They thought she must have learning difficulties. She didn’t want to read the gross story readers they set her, designed to appeal to boys. She didn’t want to do rugby or cricket, or climb ropes and lift weights. She could have grown fat from the lack of exercise, but she practiced her stretches in silence. More than once she had been beaten up for not being manly enough. She wondered if her father had set it up. He’d never be contented with two daughters instead of the son she had denied him. She’d been encouraged to be loud and outgoing as a child, even though she didn’t want to be. Her friends have always been girls, but that doesn’t mean she’s gay. She loves men, or would if she could trust them, but she’s a woman, so she’s not gay. She’s not gay! How many times does she need to remind him? Appearances are deceptive.

The final layer is me. It’s filled with thoughts of what it is like to be a man. The benefits and doubts. I wouldn’t mind changing my name if the right man came along. I sure know that it doesn’t matter. As a man, I might have a better chance of getting a good job, or I’d get to keep my work when we were married instead of staying home with the children. I wouldn’t mind staying at home with the children. That would mean we actually had some. I heard about a new technology where a sperm can be created into an egg, but I don’t think I’d want to use it. I’m sure there are hundreds of associated problems. Children seem far away. They won’t let same sex couples adopt, let alone a transgender.

There, I said it. I’m not made for the physical body I was born in. One day I’ll have the freedom to choose hormonal replacement therapy. I know it’s a lengthy process, but what in life isn’t? I’ll have to speak to the psychologists, no doubt revealing the depth of those scars that have plagued me from the beginning, and the layers I’ve acquired since I was 13. It won’t be pleasant, for them or for me. But maybe I’ll finally reach closure. Of course there are the risks of blood clots and cancer, but to be the person I am inside would be worth it. Even when I get that therapy, I might never have large breasts. I might not be curvy, except with a beautiful corset, designed to enhance whatever I do have. My mother is curvy, so those genes speak for it. But I don’t have her personality or perspectives. I’m my own person, not a sum of my parents.

Do I sound typical to you, reader? Do I? Am I the person in the mirror? Which is the real me? They’re all me. All are equally valid and invalid. Who designed me this way? I don’t know, and probably never will. But they were cruel, life is cruel. One day perhaps, I’ll have a family of my own. And I promise, my children will never feel disgusted with me, I’ll always look after them for what they are. I wouldn’t make another suffer as I have, just for being different.

A reminder that there are a number of copyrights on works published here, which can be found at http://darkthorn.sorrowfulunfounded.com/copyright/.

Thank you.

- Tetrodoxin blocks Na+ channels, nifedipine blocks Ca2+ channels

- voltage gated channel family – membrane spanning protein with 4 subunits with 6 membrane spanning domains each.

- S4 senses membrane voltage, S2 forms conducting pore

- opening/closing regulated by membrane potential

- other ion channels – cation – cellular activity, ion channel properties, spontaneous transmitter release, not regenerative

- ? is the length of an axon, the distance at which the voltage declines to ~37% of the original value (exponential decay). It depends on the diameter, membrane leakiness (Rm) and cytoplasmic crowdedness (Ri)

- active – the action potential, maintains full size (all or nothing) but is slow

- passive – fast, but decays quickly

- combined by mylination – active at the nodes of ranvier, passive between

- Na+ channels abundant in axon hillock, nodes of ranvier & soma, least in axon beneath myelin & dendrites

- K+ channels wide spread

- Ca2+ channels abundant in terminals, dendrites & areas of soma

- dimensions of color – visual system deals with variations in brightness, hue and saturation, independent of the levels of ambient light

- what you see about an object depends on the context in which it is placed

- reflects the same amount of light, but differs in perceived darkness

- illusory contours

- the visual image focused on the retina is inverted top to bottom and reversed left to right

- myopic- the image is formed before light reaches the eye

- hyperopic – plane of focus is behind the retina

- accommodation – the process by which curvature of the lens changes to allow the eye to focus on a nearby object

- near response – at the same time that accommodation occurs, the eyes converge and pupils constrict to increase depth of field of the focus

- presbyopia – the lens loses elasticity in older age, making accommodation difficult

- fovea – optimized for high acuity vision, the displacement of ganglion cells and the highest density of cone photoreceptors

- adaption to light levels by – adjustment of pupil size and adaptation of sensitivity of receptor cells

- photo receptor à bipolar cell à ganglion cell (modulated by horizontal and amacrine cells)

- cones – 4 million, three classes, low sensitivity, concentrated on fovea

- rods – 100 million, rhodopsin, high sensitivity, outside fovea

transduction in photoreceptors

1. light stimulated rhodopsin molecule activates 500 molecules of G-protein transducin. Cause GTP to bind, not GDP

2. G-protein activates a phosphodiesterase (PDE)

3. Each PDE hydrolyses 2000 molecules of cGMP

4. Reduction of cGMP causes closure of Na+ channels and hyperpolarisation of the receptor

– photoreceptors are somewhat depolarized and release glutamate in the dark

– illumination hyperpolarizes the photoreceptors, reducing glutamate release

– bipolar cells

o preserve the photoreceptor signal, glutamate is excitatory turning off ganglion cell

o invert the photoreceptor signal so that glutamate is inhibitory and ganglion cell on

decussiation of optic neurons

– the right half of the visual field projects to the left half of the brain

– the axons of ganglion cells in the nasal part of the retina cross in the optic chiasm (for information about light colors)

– the axons in the temporal part of the retina do not cross

lateral geniculate nucleus – receives projections for ganglion cells

· forms layers of cells (magnocellular from Y-cells, parvocellular from x cells.

· projections from the LGN to the cortex forms optic radiation (distinct fibre)

o topographically organized

- The hypothalamus generates homeostatic and behavioural responses to ‘interoreceptive’ stimuli

- humeral, secretion of hormones

- visceromotor, changes in the nervous system

- somatic motor, behavioral responses

- long term control of energy balance

- dual center model for regulation of feeding

- Frohlich’s syndrome – injury to the pituitary gland (WRONG!)

- role of the hypothalamus (Hetherington and Ranson)

- lesions of lateral hypothalamus – thin mouse

- lesions of anteromedial hypothalamus – fat mouse

- lipostatic theory

- the brain monitors the amount of body fat and defends this against change

- ob gene, expressed in fat cells

- db receptor, produced in brain

- leptin is produced in the fat cells and received in the brain

- decreased levels of leptin in starvation

- NPY/AgRP neurons of articulate nucleus – stimulate feeding behavior and inhibit secretion of hormones controlling ACTH & TSH

- increased levels of leptin in weight gain

- inhibit feeding behavior (MSH/CART neurons)

- stimulate release of ACTH and thyrrotropin

- NPY + AgRP – ‘oxexigenic’

- POMC + CART – ‘anorexigenic’

- Short term control of energy balance

- Ghrelin produced in stomach acts on feeding centers (NPY and AgRP), building up prior to a meal and then reduced following the meal

- Satiety signals – gastric distention and cholecystekinin and insulin

- Hedonistic feeding excites dopaminergic neurons

- language is a creative process using sounds, symbols and rules to create meanings

- language is innate, and has a specific development period (<6-7 years)

- animal sounds are steriotyped and not unique

- monkeys do not use cortical regions for communication, use brain stem

- critical period is bird song development, otherwise the sounds produced are meaningless

- language areas usually located in left hemisphere

- supramarginal gyrus, angular gyrus, Wernike’s area, Broca’s area

- deficits called aphasias

- paraphrasia – substitutions of a different word

- nonfluent speech – talking with effort (affected Broca’s area)

- agraphia – impairment in writing

- alexia – impairment in understanding written words

- Broca’s area – understand language, but can’t form or organise own sentances

- Wernike’s area – trouble understanding, but can talk

- conduction – can understand and speak well, but can’t repeat of make conversation (destruction of axons)

Classic Connectional Model

1. Sound is analysed in primary auditory cortex
2. Structure and meaning deoded by Wernike’s area
3. Motor plan for articulation is formed in Broca’s area
4. Primary motor cortex activates appropriate muscles

Left hemisphere dominant for language in right handed people.

Left handed people have less dominance.

If split brain occurs, the two hemispheres cannot determine what occurred in the other, so informtion in the right hemisphere cannot be processed into words.

Right hemisphere, involved in analysis and production of intonation and emotional content. It is used for understanding the pragmatics of language (such as interpreting jokes) in different contexts.

stimulus receptor/ action

Accessory Structures à Receptor Surface à output neurons à

energy generator potentials

potential

Translation à transduction à transmission à

Receptors

Type 1: specialized endings of sensory nerve fibers

transmit to somatosensory; proprioceptive and olfactory systems

Type 2: specialized receptor cells that connect via synapses to afferent nerve fibers

auditory, vestibular and gustatory systems

Type 3: specialized receptor cells that synapse with intermediatory cells, then nerve fibers

visual system

Stimulus à receptor cells à structural change à opening/closing

in membrane of ion channels

activated

molecules conductance change and

change in resting membrane potential

mechano receptors – mechanically gated ion channels

all other receptors – chemically gated ion channels

Coding of stimulus timing and duration à summation and adaption

Receptors fractionate (divide) the entire stimulus range into smaller blocks, allowing for coding of stimulus quality.

Temporal Summation – in order to produce a reaction, the first stimulus provides a hump for the second to leap off and reach threshold.

Spatial Summation – when there are two connections though a dendrite and the cell body (first provides hump)

Simultaneous Stimulation – two connections though the cell body make it easy to reach threshold

Facilitation – second ESP is larger than the first, then there is residual calcium in the bouton so the next stimulation has more of an action.

Metabotropic Receptors – presynaptic inhibits release

- postsynaptic slows synaptic responses and may not change membrane potential

- possess membrane spanning regions

- response transduced via G-proteins, then second messenger transduction pathways are activated

- change in membrane potential not required

Muscle Structure and Contractile Properties

- Muscle fibre – cellular element, multinucleate, each innervated, sarcomere as a functional division

- Sarcolemma – cell membrane

- Sarcoplamic reticulum – source of Ca2+ that surrounds each myofibril

- Myofibril – bundles of actin and myosin

- T-tubules – ramifying tubular system that carried the depolarization of the sarcolemma internally to each myofibril

- Sarcomere – myosin – 6 polypeptide chains, a hinge region, and ATPase activity – 400 myosin to each filament, half in one direction, half in the other

- actin – anchored to the 2-disc by protein liten – tropomysoin (covers the active sites) is regulated by troponin (calcium reactions)

Excitation-Contraction Coupling

a) motor neuron releases Ach onto skeletal muscle fiber activating the nicotinic receptors and opening K+ and Na+ channels (depolarization)

b) action potential moves away and down t-tubule system

c) dihydropyridine receptors are activated by voltage change

d) ryanodine receptors (lateral sacs of sarcolemic reticulum) open to release Ca2+

e) Ca2+ diffuses across microfilamentsa, then binds to troponin

f) Myosin heads can now bind to g-actin molecules, beginning CBC

Cross-Bridge Cycling

- Continues while nerve depolarizes membrane and ATP is present

- Shortens sarcomere to relax, Ca2+ is returned to sarcoplasmic reticulum and actin filament returns to resting position (this process occurs several times)

- Contraction velocity – ATPase activity and length of power stroke

- Contraction frequency – greater contraction strength builds piggyback response

- Muscle length – isotonic – concentric (muscle shortens) vs eccentric (muscle lengthens)

- isometric – muscle does not shorten/lengthen

- ATP provided by phosphate, anaerobic and aerobic respiration

- chemical senses – oldest and most common form of sensory system

- pheromones released for chemosensory information/communication

- reproductive behavior, identification, aggression

- chemoreceptors – generate neural signals on binding with particular chemicals

- provide quality control for injestion

Taste

- tongue, mouth, palate, pharynx, epiglottis

- taste and smell are intertwined to detect flavor

- all tastes are combinations of salt, sweet, sour, bitter (umami)

- taste preferences are inborm and present very early in life

- can develop a taste for certain types of food

- can recognize a deficiency and crave that nutrient

- whole of tongue sensitive to all basic tastes

- threshold concentration for taste

- higher concentration, less selective – specificity lies in the brain

- adaptation to higher levels of the same taste

- 2000 à 5000 taste buds on oral cavity and throat

- tastebuds located along the edge of the papillae

- receptor cell microvilli protrude from pore in chemoreceptor to contact fluid

- dissolved molecules bind to receptor, producing receptor potentials

- depolarizes à open Ca2+ channels à release neurotransmitter

- if large enough, action potentials signal taste to the brain stem

- taste stimuli

- pass through ion channels (sweet and sour)

- bind to and block ion channels (sour)

- bind to a-protein coupled receptors, not voltage gated

- are these neurons? They form synapses and transmit signals….

- saltiness – special Na+ selective channels, not voltage gated

- sourness – acidity with protons, bind to and block K+ channels

- action potentials travel along different pathways to the brain stem

- medulla of brain stem, ventral posterior medial nucleus, gustatory cortex

- population coding – integrate activity across all neurons from tastebuds

Olfaction

- oderants reach the nose through diffusion/sitting/eating

- olfactory nerves of thin unmylinated axons, only one signaling system, opening of cation channels activated Cl- channels to depolarise membrane

- response adapts quickly

- glomeruli ‘smell’ maps for olfactory discrimination