Exam 3 Final Flashcards
1
Q
Nervous System: releases neurotransmitters
A
- Molecules: neurotransmitters released in response to nerve impulses that bind to receptors on target cells but act as local messengers
- Site of action: close to site of release (at synapse) and binds to receptors on postsynaptic membrane
- Types of target cells: muscle cells, gland cells, other neurons
- Time to onset of action: within milliseconds
- Duration of action: very fast (milliseconds)
2
Q
Endocrine System: releases hormones
A
- Molecules: hormones delivered to tissues through body by blood
- Site of action: far from site of release and binds to receptors on or in target cells
- Types of target cells: all cells throughout body
- Time to onset of action: seconds, hours, or days
- Duration of action: longer (seconds to days) because hormones have to manipulate target cells = effects take longer
3
Q
Gland
A
single cell or mass of epithelial cells that specialize in secretion
4
Q
Endocrine glands
A
secretes hormones that enter the interstitial fluid and diffuses into the bloodstream
5
Q
Exocrine glands
A
don’t usually secrete hormones but secretes other substances that enter ducts that empty to the surface of a covering such as skin surface or the lumen of the stomach
6
Q
Unicellular glands + goblet cells
A
- single cells
- produces mucin (mucin +water ⇒ mucus that protects and lubricates internal body surfaces) and is an exocrine gland
7
Q
Multicellular glands
A
many cells that form distinctive microscopic structures or macroscopic organ
8
Q
Hormone action in lipid-soluble hormones
A
- Circulates around blood using transport proteins because they’re hydrophobic
- Lipid-soluble hormones diffuses into target cells and does not need to bind to receptors on cell membrane because it travels through hydrophobic part of cell membrane
- Binds to nucleus receptors that can alter gene expression that makes for a protein, thereby altering cell activity
9
Q
Hormone action in water-soluble hormones
A
- Circulates around blood freely with no need for transport proteins
- Binds to receptors in target cells that’s attached to cell membrane protein that’s connected to change-inducing messenger
- bind to G protein-coupled receptors on target cells activating enzymes such as adenylyl cyclase and cAMP which ultimately phosphorylate existing proteins leading to their activation
10
Q
Hypothalamus and pituitary gland
A
work together to control other endocrine glands and connected by infundibulum
11
Q
What hormones do the hypothalamus and anterior pituitary gland’s anterior lobe secrete? (7)
A
- growth hormone (GH)
- thyroid-stimulating hormone (TSH)
- follicle-stimulating hormone (FSH)
- luteinizing hormone (LH)
- prolactin
- adrenocorticotropic hormone
- melanocyte-stimulating hormone
12
Q
Growth hormone (GH)
A
secretes insulin-like growth factors (IGFs) = promotes growth of body tissue by acting directly on target cells to enhance lipolysis and decrease glucose uptake
13
Q
Thyroid-stimulating hormone (TSH)
A
stimulates synthesis and secretion of thyroid hormones by thyroid gland
14
Q
Follicle-stimulating hormone (FSH)
A
- Females: starts development of oocytes and induces ovarian secretion of estrogen
- Male: stimulates testes to produce sperm
15
Q
Luteinizing hormone (LH)
A
- Females: stimulates secretion of estrogens and progesterone (builds wall of uterus), ovulation, and formation of corpus luteum (yellow body)
- Males: stimulates testes to produce testosterone (primary sex hormone)
16
Q
Prolactin
A
promotes milk production by mammary glands
17
Q
Adrenocorticotropic hormone
A
stimulates secretion of glucocorticoids (mainly cortisol) by adrenal cortex
18
Q
Melanocyte-stimulating hormone
A
produces pigmentation of skin when activated by UV light, suppresses appetite, and contributes to sexual arousal
19
Q
What hormones does the hypothalamus and pituitary gland’s posterior lobe secrete? (2)
A
- Antidiuretic hormone
- Oxytocin
20
Q
Antidiuretic hormone
A
Increases facultative reabsorption of water, which decreases osmolarity of body fluids
21
Q
Oxytocin
A
- Mother’s uterus: enhances contractions
- Mother’s breasts: stimulates milk ejection by mammary glands in response to suckling
- released in response to stretch on cervix during childbirth
22
Q
What cells make up the thyroid gland and their corresponding hormones? (2)
A
- follicular cells: Triiodothyronine and thyroxine hormones / thyroid hormones
- parafollicular cells: calcitonin
23
Q
Follicular cells
A
stimulated by TSH to produce thyroxine and triiodothyronine (thyroid hormones)
24
Q
Triiodothyronine and thyroxine (thyroid hormones)
A
- Help maintain normal body temp
- increase basal metabolic rate
- stimulate synthesis of proteins
- increase ATP production
- accelerate body growth
- contribute to development of nervous system
25
Parafollicular cells
produces hormone calcitonin to help regulate calcium homeostasis
26
Calcitonin
lowers blood lvls of Ca2+ and HPO42+ by inhibiting bone resorption by osteoclasts vs. accelerating uptake of calcium and phosphates into bone extracellular matrix
27
What two cells make up the parathyroid gland?
- chief cells
- oxyphil cells
28
Chief cells
produce parathyroid hormone (PTH) that’s released when calcium lvls are low ⇒ increases Ca2+ reabsorption by kidneys, promotes calcitriol formation, increases bone resorption
29
parathyroid hormone (PTH)
increases Ca2+ reabsorption by kidneys ⇒ promotes calcitriol formation ⇒ increases bone resorption
30
Oxyphil cells
secretes excess PTH in cases of parathyroid cancer
31
The adrenal gland is divided into 2 regions, what are they?
- inner medulla
- outer cortex
32
The outer cortex of the adrenal gland is divided into 4 regions, what are they from superficial to deep and what do they each secrete?
- Zona glomerulosa: mineralocorticoids
- Zona fasciculata: Glucocorticoids
- Zona reticularis: Androgens
- Adrenal medulla: Epinephrine / Norepinephrine
33
Mineralocorticoids
- increases blood lvls of Na+ and water
- decrease blood lvl of K+
34
Glucocorticoids
- upregulate expression of anti-inflammatory proteins
- regulates blood glucose lvls by stimulating gluconeogenesis and lipolysis
35
Androgens
- helps in early growth of axillary and pubic hair in both sexes
- Females: contribute to libido and source of estrogens after menopause
36
Epinephrine / Norepinephrine
increases heart rate and blood flow to muscles ⇒ increase breathing rate ⇒ bronchodilation
37
What does the pineal gland secrete? What does that do?
Melatonin: regulate body’s biological clock
38
What does the thymus produce and what do they do?
- produces thymosin, thymic humoral factor, thymic factor, and thymopoietin
- all promote maturation of immune system’s T cells
39
What are the pancreatic islet hormones and what are they secreted by? (4)
- glucagon: secreted by alpha cells
- insulin: secreted by beta cells
- somatostatin: secreted by delta cells
- pancreatic polypeptide: secreted by F cells
40
Glucagon: secreted from alpha cells
raises blood glucose lvl by accelerating glycogenolysis and gluconeogenesis
41
Insulin: secreted from beta cells
lowers blood glucose lvl by accelerating glycogenesis ⇒ increasing lipogenesis and stimulating protein synthesis
42
Somatostatin: secreted from delta cells
inhibits secretion of insulin and glucagon ⇒ slows absorption of nutrients from GI tract
43
Pancreatic polypeptide: secreted from F cells
inhibits somatostatin secretion, gallbladder contraction, and secretion of digestive enzymes
44
What is the impact of insulin/glucagon on blood glucose lvls (controlled by negative feedback)? What are the three conditions you can get?
- hyperglycemia (chronic high blood glucose)
- Type 1 Diabetes mellitus
- Type 2 Diabetes mellitus
45
hyperglycemia (chronic high blood glucose)
- due to improper insulin secretion or insulin insensitivity
- Insufficient release of insulin and/or insulin resistance ⇒ increased glucagon release ⇒ increasing blood glucose lvls
46
Type 1 Diabetes Mellitus
autoimmune disease characterized by destruction of beta cells ⇒ little or no insulin secretion
47
Type 2 Diabetes Mellitus
hyperglycemia due to insulin resistance; target cells don’t respond to insulin normally
48
What are the growth factors? (5)
- epidermal growth factor (EGF)
- platelet-derived growth factor (PDGF)
- fibroblast growth factor (FGF)
- nerve growth factor (NGF)
- tumor angiogenesis factors (TAFs)
49
Epidermal growth factor (EGF): Secreted by salivary glands
- Stimulates proliferation of epithelial cells, neurons, neuroglia
- Suppresses cancer cells
- Secretion of gastric juice by stomach
50
Platelet-derived growth factor (PDGF): produced in blood platelets
- stimulates proliferation of neuroglia, smooth muscle fibers, and fibroblasts
- helps with wound healing
51
Fibroblast growth factor (FGF): found in pituitary gland and brain
- stimulates proliferation of smooth muscle fibers, chondrocytes, endothelial cells
- stimulates formation of new blood vessels (angiogenesis)
52
Nerve growth factor (NGF): produced in salivary glands and hippocampus of brain
- Stimulates growth of ganglia in embryo
- Maintains sympathetic nervous system
- Stimulates hypertrophy
- Stimulates neuron differentiation
53
Tumor angiogenesis factors (TAFs): produced by tumor cells
- stimulates growth of new capillaries/blood vessels, organ regeneration, and wound healing
54
Pituitary gigantism / Acromegaly
caused by excess secretion of growth hormone ⇒ overgrowth of hands, face, and feet
55
Goiter
caused by reduction or overproduction of thyroid hormone ⇒ difficulty breathing and swallowing
56
Hypothyroidism
caused by insufficient thyroid hormone ⇒ depression, weight gain, cold intolerance
57
Graves disease
caused by excess thyroid hormone ⇒ irritability, muscle weakness, heat intolerance
58
Cushing’s syndrome
caused by excess secretion of glucocorticoids ⇒ abdominal obesity, fragile skin that heals slowly, weak muscles and bones
59
Seminiferous tubules
carries sperm produced within them (spermatogenesis) out of testes
60
Spermatogenesis
- begins with spermatogonia (diploid cells) that differentiate into diploid primary spermatocytes
- Primary spermatocyte undergoes meiosis 1 to become two secondary spermatocytes (haploid) ⇒ meiosis 2 takes place and secondary spermatocytes become four spermatids
61
Sperm
- designed to reach and penetrate secondary oocyte to achieve fertilization and create zygote
- head covered by acrosome that has enzymes to help with penetration
- middle piece has mitochondira that make ATP for locomotion of sperm
- end tail and principal piece for movement
62
Ducts system structures and functions?
- efferent ducts: carries sperm to epididymis
- epididymis: where sperm matures and degenerated sperm reabsorbed + propels sperm to vas deferens
- vas deferens: sperm exits to pelvis
- spermatic cord: ascends out of scrotum
- urethra: where semen and urine passes through
63
What are the glands of the male reproductive system?
- seminal vesicles
- prostate
- bulbourethral (cowper's) glands
- semen
- penis
64
Seminal vesicles glands
secrete alkaline, viscous fluid containing fructose, prostaglandins and proteins
65
Prostate gland
secretes milky, slightly acidic fluid containing citric acid cycle, enzymes and acid phosphatase, promotes tail movement
66
Bulbourethral (Cowper’s) glands
secretes alkaline fluid during sexual arousal that neutralizes acids from urine
67
Semen
mixture of sperm and seminal fluid
68
Penis
- has glans: head of penis covered by prepuce
- contains urethra, passageway for semen and urine
69
What are the hormones that control testicular function? (5)
- gonadotropin-releasing hormone (GnRH)
- luteinizing hormone (LH)
- follicle stimulating hormone (FSH)
- testosterone
- dihydrotestosterone
70
What happens during puberty for males and GnRH is released?
- gonadotropin releasing hormone (GnRH) ⇒ that stimulates cells in anterior pituitary gland to produce luteinizing hormone (LH) and follicle stimulated hormone (FSH)
- Luteinizing hormone (LH): stimulates cells in testes to produce testosterone
- Follicle stimulated hormone (FSH): stimulates spermatogenesis
71
Testosterone and Dihydrotestosterone
- Prenatal development
- Male sexual characteristics
- Development of sexual function
- Stimulation of anabolism
72
What does the Ovaries produce?
Produces gametes (mature into ova) and hormones (progesterone, estrogens, inhibin, relaxin)
73
What are the main structures of the ovaries? (6)
- Germinal epithelium: covers surface of ovary
- Tunica albuginea: capsule of dense irregular connective tissue below germinal epithelium
- Ovarian cortex: has ovarian follicles and stromal cells
- Ovarian medulla: has connective tissue, blood vessels, lymphatic vessels and nerves
- Ovarian follicles: has oocytes in various stages of development, follicular cells, granulosa cells
- Corpus luteum: develops after ovulation when empty follicle produces progesterone, estrogen, relaxin
74
What is the main function of the Uterus and what are its 3 layers (outer --> inner)
- Where fertilized ovum will implant
- perimetrium
- myometrium (has 3 layers of smooth muscle)
- endometrium
75
Endometrium
- has Stratum functionalis layer shed every month during menstruation
- Stratum basalis layer is permanent and gives rise to new stratum functionalis after each menstruation
76
Vagina
- has Muscularis: composed of outer circular layer and inner longitudinal layer of smooth muscle ⇒ allows vaginal stretch during intercourse and childbirth
- has Hymen: thin fold of vascularized mucous membrane that partially closes inferior end of vagina
77
What are the glands of the female reproductive system? (4)
- paraurethral (skene's) glands: secretes mucus
- greater vestibular (bartholin's) glands: produces mucus during sexual arousal to provide lubrication
- bulb of vestibule: has 2 masses of erectile tissue that engorges during sexual arousal to narrow vaginal orifice ⇒ applies pressure to penis during intercourse
- mammary glands: produces milk (nipple has lactiferous ducts where milk emerges)
78
Ovarian cycle
changes that occur during and after maturation of oocyte
79
Uterine cycle
changes in endometrium that prepare it for implantation of developing embryo
80
What are the hormones involved in the female reproductive cycle?
- estrogen
- inhibin
- relaxin
- progesterone
81
Estrogen
- promotes development and maintenance of female reproductive structures and secondary sex characteristics
- increases protein anabolism
- lowers blood cholesterol
- stimulates proliferation of stratum functionalis after menstruation occurs
- if released in moderate lvls ==> stops release of GnRH, FSH, LH
82
inhibin
- stops release of FSH ==> stops development of oocytes and induces ovarian secretion of estrogen
83
Relaxin
- Inhibits contractions of uterine smooth muscle
- During labor, increases flexibility of pubic symphysis and dilates uterine cervix
84
Progesterone
- Stimulates endometrial glands to secrete glycogen and lipids, which serve as initial source for fertilized egg if implantation occurs
- If released in high lvls ==> stops release of GnRH, FSH, and LH
85
Ovarian Cycle Step-by-Step: maturation of follicle and egg
- GnRH released by hypothalamus ⇒ stimulates anterior pituitary to release FSH and LH
- FSH stimulates growth of follicle
- Follicle grows and secretes estrogen, by now FSH release is stops
- Estrogen stimulates anterior pituitary to release one last high surge of LH to finish the job of maturing the follicle
- Mature follicle with oocyte pushes against ovary wall, ruptures, and breaches wall to inject oocyte
- Damaged follicle becomes corpus luteum
- Corpus luteum secretes high levels of progesterone, moderate levels of estrogen, relaxin, and inhibin
- High levels of progesterone: inhibits release of GnRH, FSH, LH
- Moderate levels of estrogen: inhibits release of GnRH, FSH, LH
- Relaxin: inhibits contracts of uterine smooth muscle
- Inhibin: inhibits release of FSH
86
Uterine cycle Step-by-Step: prepares uterus to capture and nourish any mature fertilized egg
- Menstrual phase: corpus luteum release of progesterone and estrogen decreases to become corpus albican ⇒ shedding of stratum functionalis
- Proliferation phase: high levels of FSH and LH stimulates next round of follicles that increase estrogen secretion
- Secretory phase: new growing follicles release estrogen and progesterone ⇒ maintains vascularity in stratum functionalis
- Rising estrogen levels and growing follicles stimulates regeneration of endometrium to make it vascularized and a habitat for potential fertilized egg
- When next new egg is released in wall ⇒ post ovulatory phase begins when ruptured follicle forms and corpus luteum begins
- If no fertilization occurs: corpus luteum stops secreting progesterone ⇒ doesn’t maintain stratum functionalis nor stimulate endometrial glands to secrete nutrient for fertilized egg for implantation ⇒ menstruation occurs and stratum functionalis is shed
- If fertilization occurs: corpus luteum continues to secrete progesterone ⇒ maintains stratum functionalis and stimulates endometrial glands to secrete nutrient for fertilized egg
- Human chorionic gonadotropin (hCG) maintains corpus luteum
87
What are the birth control methods? (3)
- surgical sterilization methods (vasectomy, tubal ligation, non-incisional sterilization)
- hormonal methods
- intrauterine devices (IUDs)
88
What are the surgical sterilization methods: intervention to render person incapable of reproduction? (3)
- Vasectomy: for males, removes portion of vas deferens
- Tubal ligation: for females, ties closed and cuts uterine (fallopian) tubes
- Non-incisional sterilization: inserts coil made of plastic and metal to each uterine tube then scar tissue grows and blocks tubes
89
hormonal methods
oral contraceptives that stop pregnancy by inhibiting ovulation or thickening of cervical mucous
90
intrauterine devices (IUDs)
contains hormones or copper toxic to sperm
91
Fertilization process Step-by-Step
- enzymes of sperm's acrosome and tail movement allows sperm to penetrate corona radiata
- membrane proteins on sperm head bind to ZP3 receptor in zona pellucida
- acrosomal enzymes releases ==> makes path in zona pellucida to penetrate oocyte/egg
92
Fertilization
- merging of genetic information from haploid sperm and haploid secondary oocyte
93
Cleavage
series of mitotic division that the zygote undergoes after fertilization
94
Blastomeres
smaller cells yielded after each mitotic division that the zygote undergoes after fertilization
95
Morula
- cluster of cells that resembles mulberry
- surrounded by zona pellucida
- still the size of the zygote
96
What is a Blastocyst and its 2 different cell populations?
- rearranged blastomeres into a large, fluid filled blastocyst cavity/mass
- embryoblast (inner cell mass): develops into embryo
- trophoblast (outer cell mass): develops into outer chorionic sac that surrounds fetus and fetal portion of placenta
97
What is the Chorion and what are its functions?
- made of extraembryonic mesoderm and trophoblast that surrounds embryo
- Blocks antibody production by mother
- Promotes production of T-lymphocytes ⇒ suppresses immune response in uterus
- Produces human chorionic gonadotropin (hCG)
98
What are the 4 stages of the sensory pathway?
- Stimulation: any event that triggers specific physiological rxn in organ or tissue
- Transduction: process of converting sensory signal to electrical nerve signal process by CNS
- Sensation: conscious or subconscious awareness of changes in external or internal environment
- Perception: conscious interpretation of sensations performed mainly by cerebral cortex
99
What are the different classifications of sensory receptors by microscopic structures?
- free nerve endings: pain, thermal, tickle, itch, some touch sensations
- encapsulated nerve endings: pressure, vibration, some touch sensations
- separate cells: receptor cells synapse with first-order sensory neurons in retina of eye, inner ear, tongue's taste buds
100
What are the different classifications of sensory receptors by receptor location
- exteroceptors: sensitive to stimuli originating outside the body - hearing, vision, smell, taste, touch, vibration, pain
- interceptors: any internal environment changes and impulses aren't usually perceived but can be felt as pain or pressure
- proprioceptors: any changes to body position, muscle length, tension and position of movement joints
101
What are the different classifications of sensory receptors by type of stimulus detected? (5)
- mechanoreceptors: detects mechanical stimuli - touch, pressure, vibration, proprioception, hearing, equilibrium, and stretching of blood vessels and internal organs
- thermoreceptors: detects temp changes
- nociceptors: detects painful stimuli from physical or chemical damage to tissue
- photoreceptors: detects light that strikes eye's retina
- chemoreceptors and osmoreceptors: detects chemicals in mouth by monitoring taste, nose to smell, and any body fluid changes
102
What are the somatic sensations? (3)
- muscle spindles: type of proprioceptor that monitors muscle length and involved in stretch reflexes
- tendon organs: type of proprioceptor that protects muscles and tendons from overstretching damage
- joint kinesthetic receptors: responds to pressure, acceleration, and deceleration during movement and protects against excessive strain
103
What are the sensations of the tactile receptors of the somatic sensations? (6)
- Meissner corpuscles: onset of touch and low-frequency vibrations
- hair root plexuses: movements on skin surface that disturb hairs
- tactile discs: continuous touch and pressure
- Ruffini corpuscle: skin stretching and pressure
- Pacinian corpuscles: high-frequency vibrations
- itch and tickle receptors: itching and tickling
104
What are the somatic sensory pathways of first-order, second-order, and third-order neurons?
- first-order neurons: impulses from somatic receptors to brain stem or spinal cord
- second-order neurons: impulses from brain stem and spinal cord to thalamus
- third-order neurons: impulses from the thalamus to primary somatosensory area of cortex on the same side
105
Somatic sensory pathway
carries information from somatic sensory receptors to primary somatosensory area in cerebral cortex and to cerebellum
106
what are the 5 somatic sensory pathways?
- dorsal column-medial lemniscus (DCML) pathway
- Anterolateral pathway: has 3 pathways
- spinothalamic pathway
- spinoreticular pathway
- spinotectal pathway
- trigeminothalamic pathway
107
Dorsal column-medial lemniscus (DCML) pathway
- detects touch, vibration, proprioception, pressure from limbs, trunk, neck, and posterior head
- lesions to pathway ==> loss of vibration, joint sense, and ataxia
108
Spinothalamic pathway
- sends impulses for pain, temp, itch, and tickle
- uses 3 neurons to convey sensory info
109
spinoreticular pathway
- sends impulses for painful stimuli and causes alertness, arousal
- uses 4 lvls of neurons to convey sensory information
- pathway passes through reticular formation in brainstem to thalamus
110
spinotectal pathway
- responsible for visual reflexes due to sensations like pain, temp, tactile
- uses 3 lvls of neurons to convey sensory information
- pathway terminates in superior and inferior colliculi in midbrain
111
trigeminothalamic pathway
- sends impulses for most somatic sensations from face, nasal cavity, oral cavity, and teeth
- senses touch, proprioception, pain, and temp
112
What are 2 cells and 1 gland of the olfaction?
- supporting cells: used for physical support and nourishment for olfactory receptor cells
- basal stem cells: undergoes mitosis to replace olfactory receptor cells
- olfactory glands: produces mucus to dissolve odor molecules so that transduction occurs
113
olfactory transduction
- bindings of odorant molecule to olfactory receptor protein
- Cyclin AMP (cAMP) causes depolarization → action potential travels to primary olfactory area → travels to frontal lobe (orbitofrontal area) for odor identification
114
What are papillae and what are the 4 types of papillae?
- papillae: taste buds in elevations on tongue
- vallate papillae
- fungiform papillae
- foliate papillae
- filiform papillae
115
what are the 3 cranial nerves involved in sense of taste and what do they do?
- facial (VII) nerve: carries taste information from anterior of tongue
- glossopharyngeal (IX) nerve: carries taste information from posterior of tongue
- vagus (X) nerve: carries taste information from taste buds on epiglottis and throat
116
palpebral muscles
controls eyelid movement and extrinsic eye muscle responsible for moving eyeball
117
conjunctiva
- thin, protective mucous membrane that lines eyelids
- covers sclera
118
tarsal plate
- fold of connective tissue that give form to eyelids
- has tarsal glands: specialized sebaceous glands that keeps eyelids from sticking to each other
119
cornea
- transparent anterior portion of eye
- in eyeball's fibrous tunic layer
120
sclera
- opaque white portion of eye
- in eyeball's fibrous layer
121
choroid
- darkly-pigmented membrane that stops scattering of light rays
- in eyeball's vascular tunic layer
122
ciliary body
- thickened tissue that encircles and shapes lens
- in eyeball's vascular tunic layer
123
iris
- controls size of opening in eye (pupil) based on nervous system
124
optic disc
point where optic nerve exits eye
125
fovea centralis
- area of highest visual acuity
- center of retina
126
photoreceptors
- rods: lets us see in dim light
- cones: lets us see in bright light and produces color vision
- in retina
127
lens
- changes in shape that lets us properly focus image that's been inverted and right-to-left reversed due to refraction
128
anterior vs posterior chambers of the eye + what are they separated by?
- Anterior chamber: between iris and cornea filled with aqueous humor (clear, watery liquid)
- Posterior chamber: behind iris and in front of lens that’s filled with vitreous humor (transparent, gelatinous substance)
- both separated by iris (colored portion of eyeball)
129
How does rods let us see in the dark?
- rods release glutamate (inhibitory transmitter that inhibits the cell it's connected to)
- rods secrete glutamate ⇒ inhibits bipolar cells because that’s what they’re connected to
- inhibits ganglion cells
- brain doesn't see anything
- rod has disc membrane that has photopigment cis-retinal
- in dark, photopigment doesn't absorb light
- nothing activates transducin proteins
- cGMP is inactive
- cGMP phosphodiesterase responsible for breaking down cGMP doesn't activate
- cGMP builds up in rods because it's not being broken down, so it opens sodium channels
- sodium floods in cell
- cell is depolarized and activated
- releases inhibitory transmitter glutamate ⇒ inhibits action of bipolar cells and stops them from firing ⇒ can’t activate ganglion cells ⇒ little electrical impulses in brain ⇒ we don’t see much
130
What 4 structures make up the external ear and what do they do?
- auricle: captures sound
- external auditory canal: transmits sound to eardrum
- tympanic membrane (eardrum): vibrates according to sound waves
- ceruminous glands: secretes cerumen (earwax) to protect canal and eardrum
131
what structures make up the middle ear and what do they do?
3 auditory ossicles: amplifies sound waves that's been transmitted from eardrum on the way to oval window
132
what 2 structures make up the inner ear and what do they do?
- cochlea: translates vibrations to neural impulses that brain can interpret as sound
- semicircular canals: works with cerebellum to sense rotational acceleration for balance + responsible for dynamic equilibrium
133
saccule
senses vertical acceleration
134
utricle
senses horizontal acceleration
