2. Sensory and Edocrine

Wavelength we can and cant detect

• Can detect 380-750nm through photoreceptors

  • 3 types of cones (red, green, blue)

  • 1 type of rod

• Cant detect

  • Infrared (700+)

  • Unltraviolet(400-)

Functional properties of peripheral retina and fovea

• Peripheral retina

  • Mainly rods

  • peripheral and night vision

• Fovea

  • Mainly cones

  • High acute vision

Human vs Dog Apple

• Humans evolved from primates who had (3 cones)

  • They ate RED fruits

• Dogs evolved from wolves (2 cones)

  • Didnt need to see RED to hunt

Ear canal

• Sound waves enter ear canal → strike tympanic membrane → become vibrations

• 3 bones of middle ear vibrate (malleus, Incus, Stapes)

• Oval window in vetibular duct passes vibration from stapes into fluid waves

• Fluid waves cause vibration in basil membrane which bend inner hair cells

• The tympanic duct get hit with vibration that dissipate at round window

Stiffness of the Basilar membrane

• Low frequency sounds cause vibrations at the distal end

• High frequency sounds cause vibrations in proximal regions (close to the oval window) (stiff area)

• Wherever the vibrations occur the cilia of the IHC’s in that same region will bend and send neutral signals to the brain

3 functions of the taste system

1. Prepares body for digestion

2. Motivates or inhibits feeding

3. Identified the different chemicals in foods

   1. Umami, salt, butter, sour, sweet, or fat?

Proprioceptive vs Vestibular system contribution to movement, body awareness, and balance

Proprioception (Body position awareness)

• Stretch receptors in muscles and joints

  • Control our movement and keep track of where our body is located.

  • “Know ur hand is on a desk without looking)

Vestibular System (Balance and spatial orientation)

• Inner ear (semicircular canal)

  • detects head position and movement

  • “Know which way is up when spinning)

Functions of internal chemoreceptors and baroreceptors in the body

Chemoreceptors

• Allow us to track changes in pH, PCO₂, and PO₂ of the blood and the spinal fluid in brain and spinal cord.

• Trigger changes in breathing and cariodiovascular activity

Baroreceptors

• Allow us to monitor degree of stretch of internal cavities

  • Ex) Carotid sinus and aortic sinus (info on blood pressure and respiratory control centers)

  • Ex) lungs (info on respiratory rate)

4 somatic senses

• Somatic sensory cells/neurons

• Proprioception

• Baroreceptors

• Internal chemoreceptors

Which oral sensations are mediated by Somatic sensory receptors

• Crispness

• Oiliness

• Astringency (wine)

• Sharpness/pain

• Smoothness/Lumpiness

• Carbination

• Coldness/heat

• Spicy, pungent/tingling (spinces)

How the peripheral olfactory system discriminates odors

• Odor molecules enter the epithelum and stimulate specific types of olfactory sensory neurons

  • Green, red, or purple

• Each odor causes a unique pattern of activation of the receptor neurons

  • Glomeruli in the olfactory bulb

• Action potentials travel through the neurons and to the olfactory bulb in the brain

Comparison of nervous and endocrine systems

Nervous:

• Wierd

• Neurotransmitters diffuse over short distances

• Fast and Short lasting

• Coordinate rapid and specific responses

Endocrine:

• Wireless

• Hormones are transported over long distances in blood

• Slow and Long lasting

• Produce slower more general responses

Anterior vs Posterior pituitary gland

Posteriror Pituitary

• Secretes 2 neurohormones made by hypothalmic neurons to the blood stream

• ADH and oxytocin-

Anterior pituitary glands

• Secreates many endocrine hormone

• Made in pituitary and controled by releasing hormones from hypothalmus

• GH, TSH, ACTH

Hypthamic neurons

• Neurons in the brain

• Make neurohormone

• Sends release and inhibitory signal to anterior pituitary

• Sends neural signals to the pituitary gland to control hormone release.

Releasing hormone vs Regular Hormone

Releasing hormone

• Come from hypthalamus

• Tells anterior pituitary cell to release another hormone

• Travels through veins

Hormones

• Produced by endocrine cells

• Acts directly on target organs/tissues

• Travels through blood

Negative feedback regulating secretion of thyroid hormones

• When cortisol and thyroid hormone levels are high enough

  • They signal the hypothalamus and pituitary to stop releasing their stimulating hormones

How the body terminates hormone action

• Destroyed by enzymes in the blood or inside cells

• Reabsorbed by the secretory cells

• Excreted in urine

Target cells

• Posses specific protein receptors that bind to a hormone

target tissues for epinephrine

• lungs

• heart

• muscles

• fatty acid releae

• intestines

• liver

• brain