Section 2 Flashcards
somatic nervous system vs. autonomic nervous system
somatic
-single neuron from CNS to effect organs
-heavily myelinated axons
neurotransmitter at effector: Acetylcholine(ACh)
-effector organ: skeletal muscle
effect: stimulatory
autonomic
-two-neuron chain from CNS to effector organ
-lightly myelinated preganglionic axon
-nonmyelinated postganglionic axon
-sympathetic neurotransmitter: Norepinephrine(Ne)
-parasympatheitc neurotransmitter: Acetylcholine(ACh)
-effector organ: smooth muscle, glands, or cardiac muscle
-effect: stimulatory or inhibitory depending on neurotransmitter and receptors on effector organs
cholinergic receptors
acetylcholine(ACh)
nicotinic: agonist, stimulated by nicotine, found in neuromuscular junction and ganglions of ANS
muscarinic: agonist, stimulated by the mushroom poison muscarine, found on targets of ANS
adrenergic rceptors
responds to norepinephrine and epinephrine
found on targets of sympathetic nervous system
named: beta 1, 2, 3, and alpha 1 and 2
where is the parasympathetic from
brainstem and sacral nerves
where is the sympathetic from
thoracic and lumbar nerves
sympathetic vs. parasympathetic
sympathetic
-CNS region: thoracic and lumbar
-general effect: fight or flight; stress
-length of effect: long lasting due to hormones
-specificity of effect: diffuse effect; hormones and branching
-length of post ganglionic neuron: long
parasympathetic
-CNS region: cranial and sacral
-general effect: general house keeping effect
-length of effect: short
-specificity of effect: 1 preganglionic neuron to 1 post -> very specific
-length of postganglionic neuron: short
parasympathetic pathway
– Long pre-gang neuron, reaches all the way to target
– Releases ACh -> binds to nicotinic receptor on post-gang neuron
– Short post-gang neuron near target or embedded in target releases ACh into muscarinic receptor on target
sympathetic pathway
– Short pre-gang neuron -> each pre-gang synapses with
many post-gang neurons
– Pre-gang releases ACh and targets nicotinic receptor on post-gang neuron
– Post-gang neurons are long can travel up or down 3 options:
• Most release norepinephrine to adrenergic receptor
• A few release acetylcholine to muscarinic receptors
• Adrenal medulla substitutes for post-gang neuron releases epi and norepi into blood diffuse effects
nervous controls system
cell organ: neuron chemical released: neurotransmitter released into: synapses target tissue: neurons, muscles(all 3 types), glands signal type: frequency modulated time course: quick on/off action: direct
endocrine control system
cell organ:gland chemical released: hormone released into: blood target tissue: any cell signal type: amplitude modulated time course: slow on/ slow off action: general
neuroendocrine
cell organ: neuron chemical released: neurohormone released into: blood target tissue: any cell signal type: Frequency at neuron dictates amount of hormone released, amount of hormone dictates signal strength time course: slow on/ slow off action: general
Adenohypophysis: Hypophyseal portal
blood system
2 capillary beds connected by veins
-capillary bed in superior pituitary: takes up neurohormones from hypothalamus
-capillary bed in anterior pituitary: Drops off neurohormones from hypothalamus
Picks up hormones from anterior pituitary
-capillary bed in posterior pituitary: picks up post-pituitary hormones
Antidiuretic Hormone(ADH)
posterior pituitary
stimulus: low blood volume or high osmolarity of blood (concentrated)
inhibition: high blood volume or low osmolarity
actions: Stimulate kidneys to retain more water, Causes thirst, Increase blood pressure
Oxytocin
posterior pituitary
stimulus: nipple stimulation (breast feeding), stretch of uterus, stimulation of cervix (sexual intercourse or labor)
actions: Smooth muscle contraction:
• Uterus (labor, menstruation)
• Cervix (to aid sperm propulsion during intercourse and to prepare for labor)
• Mammary glands (let-down reflex for breast feeding)
growth hormone
Stimulate growth (protein synthesis) via insulin-like growth factors stimulates fat breakdown
thyroid stimulating hormone(TSH)
Tropic hormone (aka: thyrotropin)
• Stimulates release of thyroid hormones (T3 and T4)
• Causes growth of thyroid gland
TSH Feedback Loop and Effects
hypothalamus -TRH-> anterior pituitary -TSH-> thyroid gland -thyroid hormones-> target cells
Prolactin(PRL)
Stimulation: – Estrogen during menstrual cycle -> brief prolactin release -> breast swelling – Nipple stimulation by infant effect: – Stimulate milk production in mammary glands
Prolactin feedback loop
hypothalamus –(decrease Dopamine)PIH–> anterior pituitary –increase prolactin–> milk production
Adrenocorticotropic Hormone (ACTH)
Stimulation: – Fever, stress, low blood glucose, daily rhythm Main Effects: – Stimulate the release of cortisol from adrenal cortex – Growth of adrenal gland
ACTH loop feedback
STRESSOR -> hypothalamus -CRH-> anterior pituitary -ACTH-> adrenal -> cortisol(inhibits CRH)
thyroid gland
Very high blood flow
– 2 main types of cells:
• Follicular cells: produce thyroglobulin
– Around chamber in middle where thyroglobulin is stored
• Parafollicular cells (between follicles): produce calcitonin
hypothyroidism
Cause -Low TSH or damaged thyroid -Low iodine intake -> can’t make hormones symptoms -weakness, fatigue, cold, weight gain, goiter (if low iodine)
hyperthyroidism
causes
-pituitary tumor -> Too much TSH (can also lead to goiter)
-thyroid tumor -> too much T3 and T4
symptoms
-Weight loss, always hot and sweaty, rapid irregular heart rate, nervousness, bulging eyes (damaged CT behind eyes, Graves only)
treatment
-Remove tumor or thyroid gland -> supplement hormones for life
thyroid hormones
Triiodothyronine(T3) -contains 3 iodine molecules Tetraiodothyronine(T4) -contains 4 iodine molecules actions: – Increase metabolism • Increase mitochondrial activity • Increase protein synthesis – Involved in neural development
calcitonin
stimulus: high blood Ca2+
released by: parafollicular cells in thyroid
Actions:
– Stimulates: osteoblast activity
– Inhibits: osteoclast activity
– Resulting in: lower calcium in blood and increased bone calcium
parathyroid gland
Releases parathyroid hormone (PTH)
– Most important factor in blood calcium balance
Stimulus: low blood calcium
Actions:
– Stimulates: osteoclastic activity
– Inhibits: osteoblastic activity
– Increases Ca2+ uptake in gastrointestinal tract
Results:
– Increases plasma calcium – Decreases bone calcium
blood calcium homeostasis
high blood Ca2+ -> thyroid -calcitonin-> stimulates osteoblasts
low blood Ca2+ -> parathyroid -PTH-> stimulates osteoclasts
adrenal hormones
Threeclasses:
– Mineralcorticoids: mainly aldosterone
• Function: control mineral levels in blood
– Glucocorticoids: mainly cortisol
• Function: control blood glucose levels, control metabolism
– Gonadocorticoids: Androgens, mainly DHEA (converted to testosterone or estrogen after release)
Cortisol
Release Stimulus: – Stress release CRH – Circadian rhythm (highest in morning) Actions: – Increase blood glucose – Catabolic effects: • Protein, fat, and glycogen – Decrease inflammation – Essential to life Applications: • Cortisone injections
Cushing’s Disease
• ACTH releasing pituitary tumor
• Cortisone overdose
• Buffalo hump, high blood sugar,
muscle and bone wasting
Aldosterone
Stimulus -low blood pressure/volume -> renin form kidney -> angiotensin -High Blood K+ -Stress -> CRH -> ACTH Actions -Increased Na and water absorption in kidneys -Increased K secretion in kidneys Result -increased blood pressure/volume
mitosis vs. meiosis
Mitosis
what cell: somatic cell
daughter cell resemblance to parent: genetically identical
daughter cell resemblance to each other: genetically identical
# of chromosomes daughter vs. parent: same
purpose: cell growth, replace dead or aging cells
Meiosis
what cell: sex cells
daughter cell resemblance to parent: not identical
daughter cell resemblance to each other: not identical
# of chromosomes daughter vs. parent: half the #
purpose: reproduction
Scrotum
Out pocketing of abdominal lining
– Purpose:
3 C below body temp for sperm
cremaster
lifts testes
maintains temp
dartos
scrunches skin -> pulls testes closer to the body
maintain temp
Tunica Albuginea
in Testis
White protective layer inside
surrounds Seminiferous Tubule
Seminiferous Tubule
convoluted tubule
function: where sperm develop
epididymus
in testis
Series of ducts, posterior portion of testis
function: site of sperm maturation(become motile)
Ductus (vans) Deferens
in testis
– Connection of spermatic chord to epididymis
– Ascends through inguinal canal into abdominal cavity
– Surrounded by blood vessels, nerves and smooth muscle
ejaculation
caused by smooth muscle contraction squeezing out semen from vas deferens and spermatic chord
ejaculatory duct
- where the vas deferens and the duct of the seminal vesicle meet (before the urethra)
- wall is lined with smooth muscle foe ejaculation
urethra
duct for semen and urine
seminal vesicle
Posterior to bladder
– 70% of semen comes from here
– Secretes alkaline fluid with fructose
prostate gland
Inferior to bladder, surrounds urethra
bulbourethral glands
pea-sized, inferior to prostate
– Secrete thick, clear mucous
function: lubricate and neutralize pH of urethra prior to ejaculation
Penis
Three regions:
– Root: portion of shaft posterior to abdominal wall (inside)
– Body (shaft): external shaft
– Glans: enlarged tip, many sensory receptors
• Covered by prepuce (foreskin)
erection
parasympathetic nerves lead to nitric oxide release -> dilate arteries -> fill sinuses which smashes drainage veins -> engorgement of penis
erectile dysfunction
Cause: Damage to the artery walls with aging is the most typical
cause
• Treatment: cialis or viagra -> increase effect of nitric oxide
LH hormone
– Stimulate leydig cells to release testosterone
FSH hormone
Stimulate sertoli cells to release chemical to aid in sperm development and production
• Stimulate sertoli cells to release inhibin
testosterone
– Aids in sperm development
– Secondary male sex characteristics:
• Facial and pubic hair, deep voice, increase muscle mass
Inhibin
– Negative feedback to inhibit GnRH and FSH – Controls the rate of sperm production
anabolic steroids
• Testosterone precursors or testosterone itself
• Hypothalamus senses high testosterone -> stops GnRH -> no LH or FSH release
purpose: build muscle mass
anabolic steroid side effect
• Infertility:
– Why: no LH or FSH sertoli cells stop working and even die can lose blood barrier
• Cardiovascular disease:
– High cholesterol
– Unhealthy thickening of the heart muscle
• Liver Damage: liver metabolizes steroids
• Emotional changes: rage, instability,
depression
• Gynecomastia:
– Extra testosterone is converted into estrogen breast development
• Ulcerated acne:
– Sebaceous glands are stimulated by testosterone
ovaries
Gonads of the female: contain gametes
• Protected by: tunica albuginea
nurse cells
granulosa cells
• Organized into follicles (cavity encompassing egg)
• Surround eggs to help development (similar to sertoli)
– Many for 1 egg
– 1 sertoli for many sperm • Produce estrogen
thecal cells
Located between follicles
Function: Secrete androstenedion that turns into estrogen
Uterine Tubes (oviducts; Fallopian Tubes)
– Inner layer: Ciliated columnar epithelium
• Function: To move eggs
– Smooth muscle middle layer
• Function: to move eggs and catch eggs
– Fertilization usually occurs in uterine
tubes
Uterus
Inner layer: Endometrium
– Mucous membrane, well vascularized, many glands
– Cycles of development and necrosis of surface epithelial tissue (driven by hormones)
– Function: site of implantation and fetal development
Middle layer: Myometrium
– Majority of the thickness of uterus
– Smooth muscle, fibers oriented in all different directions
• Function: push that baby out!
Outerlayer:Perimetrium
– Serous membrane on outer layer
vagina
mostly smooth muscle and membrane • Lined by mucous membrane (stratified squamous ET) function: -sexual intercourse -passageway for menstraul flow -birth canal
hymen
outermost portion of mucous membrane: mostly blocks opening of vagina in most virgins (may bleed upon breaking)
clitoris
erectile tissue (vascular anatomy similar to penis) – Controlled by: parasympathetic nervous system
labia majora and minora
Skin folds
– Function: provide protection for vagina and urethra
vestibular glands
behind labia
– Function: secrete lubricating fluid during and before intercourse
FSH
– Stimulates follicle growth
– Stimulates granulosa cells to release estrogen – Stimulates granulosa cells to release inhibin
LH
– Stimulates thecal (interstitial) cells to produce androstenedione (converted into estrogen) causes ovulation
estrogen
– Released from follicle in response to FSH
– Stimulates growth of endometrium in uterus
progesterone
– Released from corpus luteum
– Maintains endometrium
Inhibin
– Inhibits release of FSH and GnRH
menstrual phase
days: 1-5 GnRH: low, starting to rise • LH: low, starting to rise • FSH: low, starting to rise • Progesterone: decreasing • Estrogen: decreasing • Follicle: corpus luteum dies • Uterus: endometrium dies
proliferative phase
- Days: 5-13
- GnRH: higher
- LH: higher
- FSH: higher
- Progesterone: very low
- Estrogen: rising, still low
- Follicle: growth
- Uterus: growth
ovulatory phase
- Days: 14
- GnRH: surge
- LH: surge
- FSH: surge
- Progesterone: rises after ovulation
- Estrogen: very high, drop immed
- Follicle: large, releases estrogen
- Uterus: Still growing
secretory/luteal phase
- Days: 15-28
- GnRH: low
- LH: low
- FSH: low
- Progesterone: high, from corpus luteum, inhibit 3 above
- Estrogen: from corpus luteum, stays high
- Follicle: endocrine organ, corpus luteum
- Uterus :secretes mucous, prepares for implantation
pericardium
2 layers: • Fibrous: very tough, prevents over expanding under high pressure (outermost layer) • Anchors heart to surrounding structures • Serous: 2 layered membrane with fluid in middle
epicardium
The heart side of the pericardium
pericardial cavity
Fluid filled space between the two layers of the serous membrane
myocardium
The cardiac muscle, contractile
endocardium
– Between myocardium and the heart
chamber
– Thin layer, epithelial tissue
atria
Receiving chambers pump blood to the ventricles
interatrial septum
separates left and right
foramen ovale
hole in interatrial septum of fetus
auricles
external portion, extend atria
ventricles
– Pumping chambers
– Much thicker walls, much stronger
What is the purpose of the papillary muscles in the heart?
To prevent the AV valves from turning inside out when the ventricles contract
Heart Valves
• Between atria and ventricles
Right side: tricuspid valve
Left side: bicuspid valve (mitral)
– Both have chordae tendinae attached to valve flaps and to papillary muscles
Heart Valves
• Between ventricles and associated arteries
Semilunar valves: Each have 3 (crescent moon shaped) cup like structures
– Right side: pulmonary semilunar valve
– Left side: aortic semilunar valve
What causes the AV valves to close?
pressure from blood inside ventricle
What causes the AV valves to open?
when pressure in ventricle dies down, pressure from blood coming in is greater(relaxation of ventricle)
What causes the semilunar valves to close?
left ventricle contracts, doesn’t open til ventricle has higher pressure than valve
angina
Temporary blockage or partial blockage of a portion of an artery -> chest pain
Causes:
-stress induced artery spasms
-atherosclerosis(coronary artery disease)
Treatments: nitroglycerin
myocardial infarction
- Complete blockage of artery tissue death
- Heart muscle does not heal
- Causes: Atherosclerosis -> blockage or thrombus (clot from elsewhere)
- Treatment: bypass surgery, stent
cardiac muscle fiber histology
-striated
sarcomeres identical to skeletal muscle
cardiac muscle fiber histology
-branched fibers
all connected
cardiac muscle fiber histology
-single nucleus
smaller cells
Many mitochondria (30% of volume, vs 2% in skeletal muscle)
high fatigue resistance
intercalated disks
between cells
– Desmosomes: anchoring cells together
– Gap junctions: allows ions to pass from cell to cell, action potentials pass from cell to cell
skeletal muscle
What causes an action potential?
permeability changes in membrane
what dictates an action potential in skeletal muscle?
voltage gated ion channels
cardiac action potential
• Starts in pacemaker cells (SA and AV nodes)
• Passes through gap junctions from cell to cell
• Resting membrane potential: – Balance: Negative inside
– Inside: Potassium
– Outside: Sodium
• Depolarization: by Na+ rushing in
• Plateau phase: Slow Ca2+ channels open Ca2+ rushes in
• Repolarization: Slow K+ channels open K+ goes out
conduction pathway
sinoatrial(SA) node
– Location: Upper right atrium, by vena cava
– Function: Pacemaker of heart
– Causes: atrial contraction
conduction pathway
atrioventricular(AV) node
– Location: Next to tricuspid valve
– Function: receives stim from atria sends signal to ventricles
– Causes: slight pause (.1 sec) filling time
conduction pathway
atrioventricular(AV) bundle
– Location: superior interventricular septum
– Function: only connection between ventricles, carries signal to both
conduction pathway
bundle branches
– Location: Interventricular septum, one on each side
conduction pathway
purkinje fibers
– Location: All throughout ventricles and papillary muscles
– Function: contract ventricles and papillary muscles
– Very fast depolarization rate (100 times faster than the rest)
Heart sounds
- First Sound: “lub”, due to AV valves snapping shut.
* Second Sound: “dub”, due to SL valves closing
