Unit 4 Communication and Coordination (Sensory and Endocrine Systems)

Mechanoreceptors

– stimulated by changes in pressure or movement

– Found in skin and muscles

Thermoreceptors

– stimulated by changes in temperature

– Found in skin

Pain receptors

– stimulated by tissue damage

– Found in skin and viscera

Chemoreceptors

– stimulated by changes in chemical concentration of substances

– Used for taste and smell

Photoreceptors

– stimulated by light

– Found only in the eye

cause of pain

chemicals released by inflamed tissues

referred pain

inside the body’s organs, pain is often felt in another area.

ex: pain from the heart is felt in the left shoulder and arm

papillae

(bumps) on the tongue that contain many receptors

sweet, sour, salty, bitter, umami

taste receptors can distinguish between these tastes…

pinna/auricle

label A

ear/auditory canal

label B

eardrum/tympanic membrane

label C

ossicles

label D

malleus/hammer

label D1

incus/anvil

label D2

stapes/stirrup

label D3

semicircular canals

label E

vestibule

label F

eustachian tube

label G

cochlea

label H

Auditory nerve

label I

how we hear

– 1. Sound waves travel through the auditory canal to the eardrum.

– 2. The sound waves cause the eardrum to vibrate.

– 3. The vibration causes the malleus (hammer) to hit the incus (anvil) and then the stapes (stirrup).

– 4. The vibration passes to the fluid in the cochlea of the inner ear.

– 5. Each part of the spiral cochlea is sensitive to different frequencies of sound.

– 6. The auditory nerve takes impulses to the brain.

equilibrium

– Mechanoreceptors in the semicircular canals detect rotation and movement of the head

– Little hair cells send information to the brain to cause appropriate motor output so as to correct position when it is unbalanced.

– Vertigo (dizziness)

cornea

label 1

Lens

label 3

sclera

label 4

pupil

label 14

optic disc

label 8

aqueous humor

label 13

optic nerve

label 9

iris

label 2

ciliary body

label 11

choroid

label 6

vitreous humor

label 10

retina

label 5

sclera

protection (white of eye)

cornea

refracts light (allows for it to pass through), transparent (window of the eye), only human tissue that can be transplanted w/o fear of rejection

vitreous humor

maintains eyeball shape (gel-like substance)

Retina

has photoreceptor cells that detect light and send impulses to the brain; contains rods and cones; 2 layers

Glaucoma

Damage to the optic nerve occurs due to increased eye pressure

– Can lead to blindness

Cataracts

– Clouding of the lens that affects vision

– Very common in older people

lens

focuses light; divides the eye into 2 chambers (aqueous and vitreous)

ciliary body

holds lens in place, accommodation

iris

regulates light entrance (muscle); colored part of the eye

pupil

rounded opening in the iris that admits light

hormonal stimuli

•Glands are encouraged by hormones secreted by other glands.

•Ex: Hypothalamus stimulates pituitary

humoral stimuli

•Levels of nutrients and ions in the blood can cause glands to secrete hormones.

•Ex: Blood calcium levels stimulate parathyroid glands

neural stimuli

•Nerve impulses cause glands to secrete hormones.

•Ex: Sympathetic nervous system during stress causes release of epinephrine from adrenal glands.

anterior pituitary gland

Thyroid-stimulating hormone (TSH) → Causes thyroid to produce thyroxine

Adrenocorticotropic hormone (ACTH) → Stimulates adrenal glands

Growth Hormone (GH) → Stimulates growth in bones and muscles

Melanocyte stimulating hormone (MSH) → Stimulates melanocytes to produce melanin

Prolactin (PRL) → Stimulates production of breast milk

Gonadotropins → Luteinizing hormone → Stimulates release of sex hormones

Gonadotropins → Follicle stimulating hormone → Stimulates egg or sperm production

posterior pituitary gland

Antidiuretic hormone (ADH) or vasopressin → Increases water retention in kidneys, decreasing urine production

Oxytocin (OT) → Stimulates contraction of uterus during

childbirth and promotes release of breast milk

hypothalamus

Its main function is to control the pituitary gland by hormonal and neural stimulation.

This allows for functions like:

•Control of brain stem & spinal cord

•Center of emotional response

•Body temperature regulation

•Regulation of food intake

•Controls thirst

•Regulates sleep & wake cycles

pineal gland

Melatonin → Rise and fall during day and night causing sleep and wake cycles.

thyroid gland

Calcitonin → Reduces the calcium levels in the blood

Thyroid Hormones (TH) → Thyroxine (T4) & Triiodothyronine (T3) → Regulate metabolism and body heat production, controls cellular oxygen usage, and maintains blood pressure

parathyroid gland

parathyroid hormone (PTH) → brings calcium out of the main regulator of body mineral metabolism through parathormone (PTH) actions on bone and kidney

adrenal glands

Epinephrine & Norepinephrine → Regulate the “fight or flight”

response to emergency situations. Increases heart rate, blood

pressure, blood flow, intake of oxygen for immediate

energy.

Glucocorticoids (ex: cortisol & aldosterone) → Regulate ion levels for quick energy

Pancreas

Insulin → Lower blood glucose levels

Glucagon → Raise blood glucose levels

thymus

thymopoietin, thymosin → involved in the development of the immune system.

hyposecretion

not enough hormone is released

hypersecretion

too much hormone is released

pineal gland

label 1