Castingfox101

• Flower Delivery
• Flowers Near Me
• Flowers.com
• Flowers In The Attic

• C&W Communications Plc. All rights reserved. Registered in England and Wales.
• Flow is the only layer-one blockchain originally created by a team that has consistently delivered great consumer blockchain experiences: CryptoKitties, Dapper Wallet, NBA Top Shot. The FLOW token (“FLOW”) is the native currency for the Flow network and the keystone for a new, inclusive, and borderless digital economy.

We would like to show you a description here but the site won’t allow us.

“Flow Festival is a fairytale come true.”

-Clash Magazine (UK)

“The Nordic countries’ coolest music festival”

-Vogue (US)

“Without a doubt one of the most unique experiences in live music today.”

-DIY (UK)

“Flow Festival is a fairytale come true.”

-Clash Magazine (UK)

“The Nordic countries’ coolest music festival”

-Vogue (US)

“Without a doubt one of the most unique experiences in live music today.”

-DIY (UK)

Voyetra turtle beach driver download for windows 10. “Flow Festival is a fairytale come true.”

-Clash Magazine (UK)

3-day tickets for Flow 2021 are now on sale!

Brain Facts and Figures

These data were obtained from several textbooks. All numbers are for humans unless otherwise indicated.

Table of Contents
BRAIN	NEURON	SPINAL CORD
SENSORY APPARATUS	BLOOD SUPPLY

Brain

Average Brain Weights (in grams)
Species	Weight (g)	Species	Weight (g)
adult human	1,300 - 1,400	newborn human	350 - 400
sperm whale	7,800	fin whale	6,930
elephant	4,783	humpback whale	4,675
gray whale	4,317	killer whale	5,620
bowhead whale	2,738	pilot whale	2,670
bottle-nosed dolphin	1,500 - 1,600	walrus	1,020 - 1,126
Pithecanthropus Man	850 - 1,000	camel	762
giraffe	680	hippopotamus	582
leopard seal	542	horse	532
polar bear	498	gorilla	465 - 540
cow	425-458	chimpanzee	420
orangutan	370	California sea lion	363
manatee	360	tiger	263.5
lion	240	grizzly bear	234
pig	180	jaguar	157
sheep	140	baboon	137
rhesus monkey	90-97	dog (beagle)	72
aardvark	72	beaver	45
shark (great white)	34	shark (nurse)	32
cat	30	porcupine	25
squirrel monkey	22	marmot	17
rabbit	10-13	platypus	9
alligator	8.4	squirrel	7.6
opossum	6	flying lemur	6
fairy anteater	4.4	guinea pig	4
ring-necked pheasant	4.0	hedgehog	3.35
tree shrew	3	fairy armadillo	2.5
owl	2.2	grey partridge	1.9
rat (400 g body weight)	2	hamster	1.4
elephant shrew	1.3	house sparrow	1.0
european quail	0.9	turtle	0.3-0.7
bull frog	0.24	viper	0.1
goldfish	0.097	green lizard	0.08
Reference for many of these brain weights: Blinkov, S.M. and Glezer, I.I. The Human Brain in Figures and Tables. A Quantitative Handbook, New York: Plenum Press, 1968. Demski, L.S. and Northcutt, R.G. The brain and cranial nerves of the white shark: an evolutionary perspective. In Great White Sharks. The Biology of Carcharodon carcharias, San Diego: Academic Press, 1996. Nieuwenhuys, R., Ten Donkelaar, H.J. and Nicholson, C. The CentralNervous System of Vertebrates. Vol. 3, Berlin: Springer,1998. Berta, A., et al. Marine Mammals. Evolutionary Biology, SanDiego: Academic Press, 1999. Mink, J.W., Blumenschine, R.J. and Adams, D.B. Ratio of central nervous system to body metabolism in vertebrates: its constancy and functional basis. Am. J. Physiology, 241:R203-R212, 1981. Rehkamper, G., Frahm, H.D. and Zilles, K. Quantitative development of brain and brain structures in birds (Galliformes and Passeriforms) compared to that in mammals (Insectivores and Primates). Brain Beh. Evol., 37:125-143, 1991. Ridgway, S.H. and Harrison, S., Handbook of Marine Mammals, Vol. 3, London: Academic Press, 1985. Shoshani, J., Kupsky, W.J. and Marchant, G.H., Elephant brain. Part I: Gross morphology functions, comparative anatomy, and evolution, Brain Res. Bulletin, 70:124-157, 2006.

% brain of total body weight (150 pound human) = 2%
Average brain width = 140 mm
Average brain length = 167 mm
Average brain height = 93 mm

Intracranial contents by volume (1,700 ml, 100%): brain = 1,400 ml (80%); blood = 150 ml (10%); cerebrospinal fluid = 150 ml (10%) (from Rengachary, S.S. and Ellenbogen, R.G., editors, Principles of Neurosurgery, Edinburgh: Elsevier Mosby, 2005)

Average number of neurons in the brain = 86 billion (Frederico Azevedo et al., Equal numbers of neuronal and nonneuronal cellsmake the human brain an isometrically scaled-up primate brain. J. Comp.Neurol., 513: 532-541, 2009.)
The octopus nervous system has about 500,000,000 neurons, with two-thirds of these neurons located in the arms of the octopus. (Hochner, B. et al., The octopus: a model for a comparative analysis of the evolution of learning and memory mechanisms, Biol Bull., 210:308-317, 2006.)
Number of neurons in honey bee brain = 950,000 (from Menzel, R. and Giurfa, M., Cognitive architectureof a mini-brain: the honeybee, Trd. Cog. Sci., 5:62-71, 2001.)
Number of neurons in Aplysia nervous system = 18,000-20,000
Number of neurons in each segmental ganglia in the leech = 350
Volume of the brain of a locust = 6mm³(fromThe Neurobiology of the Insect Brain, Burrows, M., 1996)

Ratio of the volume of grey matter to white matter in the cerebralhemipheres (20 yrs. old) = 1.3 (Miller, A.K., Alston,R.L. and Corsellis, J.A., Variation with age in the volumes of grey andwhite matter in the cerebral hemispheres of man: measurements with animage analyser, Neuropathol Appl Neurobiol., 6:119-132, 1980)
Ratio of the volume of grey matter to white matter in the cerebral hemipheres (50 yrs. old) = 1.1 (Miller et al., 1980)
Ratio of the volume of grey matter to white matter in the cerebral hemipheres (100 yrs. old) = 1.5 (Miller et al., 1980)
% of cerebral oxygen consumption by white matter = 6%
% of cerebral oxygen consumption by gray matter = 94%

Ratio of glial cells to neurons in the brain = 1:1 (Reference 1 and Reference 2)

(For more information about the number of neurons in the brain, see R.W. Williams and K. Herrup, Ann. Review Neuroscience, 11:423-453, 1988)

Number of neocortical neurons (females) = 19.3 billion (Pakkenberg, B. et al., Aging and the human neocortex, Exp. Gerontology, 38:95-99, 2003 and Pakkenberg, B. and Gundersen, H.J.G. Neocortical neuron number in humans: effect of sex and age. J. Comp.Neurology, 384:312-320, 1997.)
Number of neocortical neurons (males) = 22.8 billion (Pakkenberg et al., 1997; 2003)
Average loss of neocortical neurons = 85,000 per day (~31 million per year) (Pakkenberg et al., 1997; 2003)
Average loss of neocortical neurons = 1 per second (Pakkenberg et al.,1997; 2003)
Average number of neocortical glial cells (young adults ) = 39 billion (Pakkenberg et al., 1997; 2003)
Average number of neocortical glial cells (older adults) =36 billion (Pakkenberg et al., 1997; 2003)
Number of neurons in cerebral cortex (rat) = 21 million (Korbo, L., et al., J. Neurosci Methods, 31:93-100, 1990)
Length of myelinated nerve fibers in brain = 150,000-180,000 km (Pakkenberg et al., 1997; 2003)
Number of synapses in cortex = 0.15 quadrillion (Pakkenberg et al.,1997; 2003)
Difference number of neurons in the right and left hemispheres = 186 million MORE neurons on left side than right side (Pakkenberg et al.,1997; 2003)

Proportion by Volume (%)
Rat	Human
Cerebral Cortex	31	77
Diencephalon	7	4
Midbrain	6	4
Hindbrain	7	2
Cerebellum	10	10
Spinal Cord	35	2
(Reference: Trends inNeurosciences, 18:471-474, 1995)

Composition of Brain and Muscle
Skeletal Muscle (%)	Whole Brain (%)
Water	75	77 to 78
Lipids	5	10 to 12
Protein	18 to 20	8
Carbohydrate	1	1
Soluble organic substances	3 to 5	2
Inorganic salts	1	1
(Reference: McIlwain, H. and Bachelard, H.S., Biochemistry and the Central Nervous System, Edinburgh: Churchill Livingstone, 1985)

Total surface area of the cerebral cortex = 2,500 cm² (2.5ft²; A. Peters, and E.G. Jones, Cerebral Cortex, 1984)

Total surface area of the cerebral cortex (lesser shrew) = 0.8 cm²
Total surface area of the cerebral cortex (rat) = 6 cm²
Total surface area of the cerebral cortex (cat) = 83 cm²
Total surface area of the cerebral cortex (African elephant) = 6,300 cm²
Total surface area of the cerebral cortex (Bottlenosed dolphin) = 3,745 cm²(S.H. Ridgway, The Cetacean Central Nervous System, p. 221)
Total surface area of the cerebral cortex (pilot whale) = 5,800 cm²
Total surface area of the cerebral cortex (false killer whale) = 7,400 cm²
(Reference for surface area figures: Nieuwenhuys, R., Ten Donkelaar, H.J. and Nicholson, C., The Central nervous System of Vertebrates, Vol. 3, Berlin: Springer, 1998)
Total number of neurons in cerebral cortex = 10 billion (from G.M. Shepherd, The Synaptic Organization of theBrain, 1998, p. 6). However, C. Koch lists the total number of neurons in the cerebral cortex at 20 billion (Biophysics of Computation. Information Processing in Single Neurons, New York: Oxford Univ. Press, 1999, page 87).
Total number of synapses in cerebral cortex = 60 trillion (yes, trillion)(from G.M. Shepherd, The Synaptic Organization of theBrain, 1998, p. 6). However, C. Koch lists the total synapses in the cerebral cortex at 240 trillion (Biophysics of Computation.Information Processing in Single Neurons, New York: Oxford Univ.Press, 1999, page 87).

Percentage of total cerebral cortex volume (human): frontal lobe = 41%; temporal lobe = 22%; parietal lobe = 19%; occipital lobe = 18%. (Kennedy et al., Cerebral Cortex, 8:372-384, 1998.)

Number of cortical layers = 6
Thickness of cerebral cortex =1.5-4.5 mm
Thickness of cerebral cortex (Bottlenosed dolphin) =1.3-1.8 mm (S.H. Ridgway, The Cetacean Central NervousSystem, p. 221)

EEG - beta wave frequency = 13 to 30 Hz
EEG - alpha wave frequency = 8 to 13 Hz
EEG - theta wave frequency = 4 to 7 Hz
EEG - delta wave frequency = 0.5 to 4 Hz
World record, time without sleep = 264 hours (11 days) by Randy Gardner in 1965. Note: In Biopsychology (by J.P.J. Pinel, Boston: Allyn andBacon, 2000, p. Wetelecom driver download for windows. 322), the record for time awake is attributed to Mrs.Maureen Weston. She apparently spent 449 hours [18 days, 17 hours] awakein a rocking chair. The Guinness Book of World Records[1990] has the record belonging to Robert McDonald who spent453 hours, 40 min in a rocking chair.
Time until unconsciousness after loss of blood supply to brain = 8-10 sec
Time until reflex loss after loss of blood supply to brain = 40-110 sec

Rate of neuron growth (early pregnancy) = 250,000 neurons/minute
Length of spiny terminals of a Purkinje cell = 40,700 micron
Number spines on a Purkinje cell dendritic branchlet = 61,000
Surface area of cerebellar cortex = 1,590 cm² (from Sereno et al., The human cerebellum has almost 80% of the surface area of the neocortex, PNAS, 117:19538-19543, 2020
Weight of adult cerebellum = 150 grams (Afifi, A.K. and Bergman, R.A., Functional Neuroanatomy, New York: McGraw-Hill, 1998)
Number of Purkinje cells = 15-26 million
Number of synapses made on a Purkinje cell = up to 200,000
Weight of hypothalamus = 4 g
Volume of suprachiasmatic nucleus = 0.3 mm³
Number of fibers in pyramidal tract above decussation = 1,100,000
Number of fibers in corpus callosum = 200,000,000 (Lunders, E., Thompson, P.M. and Toga, A.W., The Development of the Corpus Callosum in the Healthy Human Brain, The Journal of Neuroscience, 30:10985-10990, 2010.)
Area of the corpus callosum (midsagittal section) = 6.2 cm²

Species	Cerebellum Weight (grams)	Body Weight (grams)
Mouse	0.09	58
Bat	0.09	30
Flying Fox	0.3	130
Pigeon	0.4	500
Guinea Pig	0.9	485
Squirrel	1.5	350
Chinchilla	1.7	500
Rabbit	1.9	1,800
Hare	2.3	3,000
Cat	5.3	3,500
Dog	6.0	3,500
Macaque	7.8	6,000
Sheep	21.5	25,000
Bovine	35.7	300,000
Human	142	60,000
Sultan, F. and Braitenberg, V. Shapes and sizes of different mammalian cerebella. A study in quantitative comparative neuroanatomy. J. Hirnforsch., 34:79-92, 1993.

Total volume of cerebrospinal fluid (adult) = 125-150 ml
Total volume of cerebrospinal fluid (infant) = 50 ml (Aghababian, R., Essentials of Emergency Medicine, 2006)
Turnover of entire volume of cerebrospinal fluid = 3 to 4 times per day (from Kandel et al., 2000, p. 1296)
Rate of production of CSF = 0.35 ml/min (500 ml/day) (from Kandel et al., 2000, p. 1296)
pH of cerebrospinal fluid = 7.33 (from Kandel et al., 2000, p. 1296)
Specific gravity of cerebrospinal fluid = 1.007
Color of normal CSF = clear and colorless
White blood cell count in CSF = 0-3 per mm³
Red blood cell count in CSF = 0-5 per mm³
Normal intracranial pressure = 150 - 180 mm of water

Composition of Serum and Cerebrospinal Fluid (CSF)
CSF	Serum
Water (%)	99	93
Protein (mg/dl)	35	7000
Glucose (mg/dl)	60	90
Osmolarity (mOsm/l)	295	295
Na (meq/l)	138	138
K (meq/l)	2.8	4.5
Ca (meq/l)	2.1	4.8
Mg (meq/l)	0.3	1.7
Cl (meq/l)	119	102
pH	7.33	7.41
(Reference: Fishman, R.A. Cerebrospinal Fluid in Disease of the Nervous System. Philadelphia: Saunders, 1980)

Number of cranial nerves = 12

I- olfactory

II- optic

Number of fibers in human optic nerve = 1,200,000
Number of fibers in cat optic nerve = 119,000
Number of fibers in albino rat optic nerve = 74,800
Length of optic nerve = 50 mm (Reference: Kanski, J.J., Clinical Ophthalmology, 6th ed., Edinburgh: Elsevier, 2007.)

III- oculomotor

Number of fibers in oculomotor nerve = 25,000-35,000

IV- trochlear

Number of fibers in trochlear nerve = 2,000-3,500
Number of neurons in nucleus of the trochlear nerve = 2,000-3,500

V- trigeminal

Number of fibers in motor root of trigeminal nerve = 8,100
Number of fibers in sensory root of trigeminal nerve = 140,000

VI- abducens

Number of fibers in abducens nerve (at exit from brain stem) = 3,700

VII- facial

Number of fibers in facial nerve (at exit from brain stem) = 9,000-10,000
Length of nucleus of the facial nerve = 2 to 5.6 mm
Number of neurons in nucleus of the facial nerve = 7,000

VIII-vestibulocochlear
IX- glossopharyngeal
X- vagus

Length of dorsal motor nucleus of the vagus nerve = 10 mm

XI- spinal accessory
XII- hypoglossal

Number of neurons in nucleus of the hypoglossal nerve = 4,500-7,500
Length of nucleus of the hypoglossal nerve = 10 mm

Spinal Cord

Number of neurons in human spinal cord = 1 billion (from Kalat, J.W., Biological Psychology, 6th Edition, 1998, page 24)
Length of human spinal cord = 45 cm (male); 43 cm (female)
Length of human vertebral column (male) = 71 cm
Length of human vertebral column (female) = 61 cm
Length of cat spinal cord = 34 cm
Length of rabbit spinal cord = 18 cm
Length of the filum terminale = 15 cm

Cross sectional area of the spinal cord (C2 level) = 110 mm²
Cross sectional area of the spinal cord (C4 level) = 122 mm²
Cross sectional area of the spinal cord (C5 level) = 78 mm²
Cross sectional area of the spinal cord (C7 level) = 85 mm²
(Reference: Watson, C., Paxinos, G. and Kayalioglu, G., The Spinal Cord, Amsterdam: Elsevier, 2009)

Weight of human spinal cord = 35 g
Weight of rabbit spinal cord = 4 g
Weight of rat spinal cord (400 g body weight) = 0.7 g
Maximal circumference of cervical enlargement = 38 mm
Maximal circumference of lumbar enlargement = 35 mm
Pairs of Spinal Nerves = 31
Number of spinal cord segments (human)= 31

8 cervical segments
12 thoracic segments
5 lumbar segments
5 sacral segments
1 coccygeal segment

Number of Spinal Cord segments (rat)= 34

8 cervical segments
13 thoracic segments
6 lumbar segments
4 sacral segments
3 coccygeal segments

Sensory Apparatus

Audition

Surface area of the tympanic membrane = 85mm² (Hearing: Its Physiology and Pathophysiology, A.R. Moller, Amsterdam: Elsevier, 2006)
Length of the eustachian tube = 3.5 to 3.9 cm (Hearing. Its Physiology and Pathophysiology, A.R. Moller, San Diego, Academic Press, 2000.)
Number of hair cells in cochlea = 3,500 inner hair cells; 12,000 outer hair cells (Hearing. ItsPhysiology and Pathophysiology, A.R. Moller, San Diego, Academic Press, 2000.)
Number of fibers in auditory nerve = 30,000 (Hearing: Its Physiology and Pathophysiology, A.R.Moller, Amsterdam: Elsevier, 2006)
Length of auditory nerve = 2.5 cm (Hearing: Its Physiology and Pathophysiology, A.R.Moller, Amsterdam: Elsevier, 2006)
Number of neurons in cochlear nuclei = 8,800 (Northern, J.L. and Downs, M.P., Hearing in Children, 5th edition, Philadelphia: Lippincott Williams & Wilkins, 2002.)
Number of neurons in inferior colliculus = 392,000 (Northern, J.L. and Downs, M.P., Hearing in Children, 5th edition, Philadelphia: Lippincott Williams & Wilkins, 2002.)
Number of neurons in medial geniculate body = 570,000
Number of neurons in auditory cortex = 100,000,000
Hearing Range (young adult human) = 20 to 20,000 Hz
Hearing Range (elderly human) = 50 to 8,000 Hz (Guyton, A.C., Textbook of Medical Physiology, 1986)
Hearing Range (rat) = 1,000 to 50,000 Hz
Hearing Range (cat) = 100 to 60,000 Hz
Hearing Range (dolphin) = 200 to 150,000 Hz
Hearing Range (elephant) = 1 to 20,000 Hz
Hearing Range (goldfish) = 5 to 2,000 Hz
Hearing Range (moth, noctuid) = 1,000 to 240,000 Hz
Hearing Range (mouse) = 1,000 to 100,000 Hz
Hearing Range (sea lion) = 100 to 40,000 Hz
(Hearing range reference: Discover Science Almanac, New York: Hyperion, 2003)
Most sensitive range of human hearing = 1,000-4,000 Hz
Length of external auditory meatus (ear canal) = 2.7 cm

Diameter of external auditory meatus (ear canal)= 0.7 cm
Weight of malleus = 23 mg; length of malleus = 8-9 mm
Weight of incus = 30 mg; dimensions of incus = 5 mm by 7 mm
Weight of stapes = 3-4 mg; dimensions of stapes = 3.5 mm high, 3 mm long, 1.4 mm wide
Malleus, incus and stapes references: Gelfand, S.A. Hearing: An Introduction to Psychological and Physiological Acoustics, 4th edition, New York: Marcel Dekker, 2004.

Length of cochlea = 35 mm
Width of cochlea = 10 mm
Number of turns in the cochlea = 2.2-2.9
Length of basilar membrane = 25-35 mm
Width of basilar membrane = 150 microns (at base of cochlea) (Hearing. Its Physiology and Pathophysiology, A.R. Moller, San Diego, Academic Press, 2000.)
Auditory Pain Threshold = 130 db
Threshold for hearing damage = 90 db for an extended period of time

Decibel Sound Scale
Decibels	Sound
180	Rocket launching pad
140	Jet plane
140	Gunshot blast
120	Automobile horn
130	Pain threshold
120	Discomfort
90	Subway
80	Noisy Restaurant
75	Busy traffic
66	Normal conversation
50	Average home
30	Soft whisper
Source: Lee, K.J., Essential Otolaryngology, 8th edition, New York: McGraw-Hill, 2003.

Taste

Total number of human taste buds (tongue, palate, cheeks) = 10,000
Number of taste buds on the tongue = 9,000
Height of taste bud = 50-100 microns (From: Farbman, A.I., Taste Bud, in G. Adelman, eds., Encyclopedia of Neuroscience, 1987)
Diameter of taste bud = 30-60 microns (From: Farbman, A.I.)
Number of receptors on each taste bud = 50-150 (Boron, W.F. and Boulpaep, E.L., Medical Physiology. A Cellular and Molecular Approach, Philadelphia: Saunders, 2003)
Diameter of taste receptor = 10 micron
Diameter of taste fiber = less than 4 micron
Taste threshold for quinine sulfate = 3.376 mg/liter water

Smell

Number of human olfactory receptor cells = 12 million (Shier, D., Butler, J. and Lewis, R. Hole's Human Anatomy & Physiology, Boston: McGraw Hill, 2004)
Number of rabbit olfactory receptor cells = 100 million
Number of dog olfactory receptor cells = 1 billion
Number of bloodhound olfactory receptor cells = 4 billion (Shier, D., Butler, J. and Lewis, R. Hole's Human Anatomy & Physiology, Boston: McGraw Hill, 2004)
Surface area of olfactory epithelium (contains olfactory receptor cells) in humans = 10 cm²(Bear, M.F., Connors, B.W. and Pradiso, M.A., Neuroscience: Exploring the Brain, 2nd edition, Baltimore: Lippincott Williams and Wilkins, 2001, p. 269)
Surface area of bloodhound olfactory epithelium = 59 in²(Shier, D., Butler, J. and Lewis, R. Hole's Human Anatomy & Physiology, Boston: McGraw Hill, 2004)
Area of olfactory epithelium in some dogs = 170 cm² (Bear, M.F., Connors, B.W. and Pradiso, M.A., Neuroscience: Exploring the Brain, 2nd edition, Baltimore: Lippincott Williams and Wilkins, 2001, p. 269)
Area of olfactory epithelium in cats = 21 cm²(Bradshaw, J., Behavioral biology, in The Waltham Book of Dog and Cat Behaviour, ed. C. Thorne, Oxford: Pergamon Press, 1992)
Thickness of olfactory epithelium mucous layer = 20-50 microns. (Boron and Boulpaep, 2003)
Diameter of olfactory receptor axons = 0.1-0.2 micron
Diameter of distal end olfactory receptor cell = 1 micron
Diameter of olfactory receptor cell = 40-50 micron
Number of cilia per olfactory receptor cell = 10-30
Length of cilia on olfactory receptor cell = 100-150 micron
Concentration for detection threshold of musk = 0.00004 mg/liter air
The volume of the human olfactory bulb is 0.06 cm³. (Kavoi, B.M. and Jameela, H., Comparative morphometry of the olfactory bulb, tract, and stria in the human, dog, and goat. Int. J. Morphol. 29, 939-946, 2011.)
The volume of the dog olfactory bulb is 0.18 cm³. (Kavoi, B.M. and Jameela, H., Comparative morphometry of the olfactory bulb, tract, and stria in the human, dog, and goat. Int. J. Morphol. 29, 939-946, 2011.)
The volume of the goat olfactory bulb is 0.17 cm³. (Kavoi, B.M. and Jameela, H., Comparative morphometry of the olfactory bulb, tract, and stria in the human, dog, and goat. Int. J. Morphol. 29, 939-946, 2011.)
The olfactory bulb is about 0.01% of the human brain by volume and 2% of the mouse brain by volume. (McGann, J.P., Poor human olfaction is a 19th-century myth, Science, Volume 356 Issue 6338, eaam7263DOI: 10.1126/science.aam7263, 2017)

Vision

Length of eyeball (adult) = 24.2 mm (from Riordan-Eva, P. and Whitcher, J.P., Vaughan & Asbury's General Ophthalmology, 17th ed., New York: Lange Medical Books, 2008)
Length of eyeball (newborn) = 16.5 mm (from Riordan-Eva and Whitcher, 2008)
Volume of eyeball = 5.5 cm³
Weight of eyeball = 7.5 g
Average time between blinks = 2.8 seconds
Average duration of a single blink = 0.1-0.4 seconds (Schiffman, H.R., Sensation and Perception. An Integrated Approach, New York: John Wiley and Sons, Inc., 2001)
Thickness of cornea = ~0.5 mm in center; ~1 mm in periphery (Foster, C.S., Azar, D.T. and Dohlman, C.H. Smolin and Thoft's The Cornea. Scientific Foundations and Clinical Practice, 4th edition, Philadelphia: Lippincott Williams & Wilkins, 2005)
Diameter of cornea = 11.5 mm
Thickness of lens = 4 mm (from Riordan-Evaand Whitcher, 2008)
Diameter of lens = 9 mm (from Riordan-Evaand Whitcher, 2008)
Composition of lens = 65% water; 35% protein (from Riordan-Eva and Whitcher, 2008)
Nerves in lens = 0 (from Riordan-Evaand Whitcher, 2008)
Blood vessels in lens = 0 (from Riordan-Evaand Whitcher, 2008)
Number of retinal receptor cells = 5-6 million cones; 120-140 millionrods
Number of retinal ganglion cells = 800 thousand to 1 million
Number of fibers in optic nerve = 1,200,000
Number of neurons in lateral geniculate body = 570,000
Number of cells in visual cortex (area 17) = 538,000,000
Wavelength of visible light (human) = 400-700 nm
Amount of light necessary to excite a rod = 1 photon
Amount of light necessary to excite a cone = 100 photons
Location of the greatest density of rods = 20^o from fovea
Highest density of rods = 160,000 per mm²
Peak density of rods (cat) = 400,000 per mm²
Density of cones in fovea = 200,000 per mm²
Diameter of fovea = 1.5 mm
Intraocular pressure = 10-20 mm Hg
Volume of orbit = 30 ml
Area of retina = 2,500 mm²
Thickness of retina = 120 microns (ranges from 100 to 230 microns)
Production rate of aqueous humor = 2 microliters/min
Turnover of aqueous humor = 15 times/day
% volume of eye occupied by the vitreous = 80%
Maximal sensitivity of red cones = 570 nm
Maximal sensitivity of green cones = 540 nm
Maximal sensitivity of blue cones = 440 nm
Area of the primary visual cortex = 4.5 mm² (mice), 1200 mm² (macaque monkeys), 3000mm² (humans) (Source: Kaas, J.H. (1989). Why does the brain have so many visual areas? J. Cogn. Neurosci. 1, 121-135.)
More Factsand Figures about the Human Retina from WebVision.

Touch

Weight of skin (adult human) = 9 lb.(4.1 kg)(Source: Schiffman, H.R., Sensation andPerception. An Integrated Approach, New York: John Wiley and Sons,Inc., 2001)
Surface area of skin (adult human) = 3,000 in² (~1.8 m²) (Source: Schiffman, H.R., Sensation andPerception. An Integrated Approach, New York: John Wiley and Sons,Inc., 2001)
Number of tactile receptors in the hand = 17,000
Number of nerve endings in hand = 1,300 per in²
von Frey threshold (Face) = 5 mg
2 point threshold (Finger) = 2-3 mm
Length of Meissner corpuscle = 90 - 120 micron
Density of receptors on finger tips = 2,500 per cm²
Density of Meissner's corpuscles on finger tips = 1,500 per cm²
Density of Merkel's cells on finger tips = 750 per cm²
Density of Pacinian corpuscles on finger tips = 75 per cm²
Density of Ruffini's corpuscles on finger tips = 75 per cm

Flower Delivery

²
Thermal pain threshold = 45^oC

Flowers Near Me

Neurons

Mass of a large sensory neuron = 10^-6gram (from Groves and Rebec, Introduction to Biological Psychology Download walter oney software usb devices driver. , 3rd edition, Dubuque: Wm.C. Brown Publ., 1988)
Number of synapses for a 'typical' neuron = 1,000 to 10,000
Diameter of neuron = 4 micron (granule cell) to 100 micron (motor neuron in cord)
Diameter of neuron nucleus = 3 to 18 micron
Length of Giraffe primary afferent axon (from toe to neck) = 15 feet
Resting potential of squid giant axon = -70 mV
Conduction velocity of action potential = 0.6-120 m/s (1.2-250 miles/hr)

Single sodium pump maximum transport rate = 200 Na ions/sec; 130 K ions/sec
Typical number of sodium pumps = 1000 pumps/micron² of membrane surface (from Willis and Grossman, MedicalNeurobiology, Mosby, St. Louis, 1981, p. 36)
Total number of sodium pumps for a small neuron = 1 million
Density of sodium channels (squid giant axon) = 300 per micron²(from Hille, B., Ionic Channels of ExcitableMembranes, Sinauer, Sunderland, 1984, p. 210.)
Number of voltage-gated sodium channels at each node = 1,000 to 2,000 permicron² (from Nolte, J., The Human Brain, Mosby,1999, p. 163.)
Number of voltage-gated sodium channels between nodes = 25 per micron² (from Nolte, J., The Human Brain, Mosby,1999, p. 163.)
Number of voltage-gated sodium channels in unmyelinated axon = 100 to 200 per micron² (from Nolte, J., The Human Brain, Mosby, 1999, p. 163.)
Diameter of ion channel = 0.5 nanometer (Breedlove et al.,Biological Psychology, 2007)
Diameter of microtubule= 20 nanometer
Diameter of microfilament = 5 nanometer
Diameter of neurofilament = 10 nanometer
Thickness of neuronal membrane = 5 nanometer (Breedlove et al., Biological Psychology, 2007)
Thickness of squid giant axon membrane = 50-100 A
Membrane surface area of a typical neuron = 250,000 um² (Bear et al., 2001)
Membrane surface area of 100 billion neurons = 25,000 m², the size of four soccer fields (Bear, M.F.,Connors, B.W. and Pradiso, M.A., Neuroscience: Exploring the Brain, 2ndedition, Baltimore: Lippincott Williams and Wilkins, 2001, p. 97)

Typical synaptic cleft distance = 20-40 nanometers across (from Kandel et al., 2000, p. 176)
% neurons stained by the Golgi method = 5%
Slow axoplasmic transport rate = 0.2-4 mm/day (actin, tubulin)
Intermediate axoplasmic transport rate = 15-50 mm/day (mitochondrial protein)
Fast axoplasmic transport rate = 200-400 mm/day (peptides, glyolipids)
Number of molecules of neurotransmitter in one synaptic vesicle = 5,000 (from Kandel et al., 2000, p. 277)
Diameter of synaptic vesicle = 50 nanometer (small); 70-200 nanometer (large)
Diameter of neurofilament = 7 - 10 nm
Diameter of microtubule = 25 nm
Internodal Length = 150 - 1500 microns (depends on fiber diameter)
% composition of myelin = 70-80% lipid; 20-30% protein

Flowers.com

Ion Concentration (mM) - SQUID NEURON
Intracellular	Extracellular
Potassium	400	20
Sodium	50	440
Chloride	40-150	560
Calcium	0.0001	10
Ion Concentration (mM) - MAMMALIAN NEURON
Intracellular	Extracellular
Potassium	140	5
Sodium	5-15	145
Chloride	4-30	110
Calcium	0.0001	1-2
Data from Purves et al., Neuroscience, Sunderland: Sinauer Associates,1997.

% brain utilization of total resting oxygen = 20%
% blood flow from heart to brain = 15-20% (Kandel et al., 2000)
Blood flow through whole brain (adult) = 750-1000 ml/min
Blood flow through whole brain (adult) = 54 ml/100 g/min
Blood flow through whole brain (child) = 105 ml/100 g/min
Cerebral blood flow = 55 to 60 ml/100 g brain tissue/min
Cerebral blood flow (gray matter) = 75 ml/100 g brain tissue/min
Cerebral blood flow (white matter) = 45 ml/100 g brain tissue/min (Rengachary, S.S. and Ellenbogen, R.G., editors, Principles ofNeurosurgery, Edinburgh: Elsevier Mosby, 2005)
Oxygen consumption whole brain = 46 cm³/min
Oxygen consumption whole brain = 3.3 ml/100 g/min
Blood flow rate through each carotid artery = 350 ml/min (Kandel et al., Principles of Neural Science, New York: McGraw Hill, 2000)
Blood flow rate through basilar artery = 100-200 ml/min (Kandel et al., 2000)
Diameter of vertebral artery = 2-3 mm
Diameter of common carotid artery (adult) = 6 mm
Diameter of common carotid artery (newborn) = 2.5 mm
The total length of capillaries in the human brain = ~400 miles (Cipolla, M.J., The Cerebral Circulation, San Rafael (CA: Morgan & Claypool Life Sciences, 2009.)

Flowers In The Attic

[Return to Neuroscience for Kids] | [Return toEric H. Chudler's Home Page]