organ systems

nervous, muscles, respiratory, circulatory, lymphatic,

main source of energy for neurons

glucose

oligodendrocytes

produce myelin in the CNS

Schwann cells

produce myelin in PNS

microglia

phagocytes in the cerebrospinal fluid

immune function

ependymal cells

circulate the cerebrospinal fluid (and nourishment) with cilia

astrocytes

in blood brain barrier, provide support and nourishment

refractory periods

absolute: no AP because during AP or inactivated Na channels

relative: possible AP during hyperpolarization, must be strong signal to overcome the hyperpolarization

EPSP

excitatory: depolarizes post synaptic neuron

• opens Na+ channels

IPSP

inhibitory: hyperpolarized post synaptic neuron

• opens K+ channels

Acetylcholine

NT at neuromuscular junction that is excitatory

• causes contraction

  • broken down by acetylcholine esterase in membrane of post synaptic cell

Glutamate

AA NT

• most common excitatory in CNS

  • memory formation

Gamma aminobutyric acid

(GABA) AA NT

• most common inhibitory in brain

Glycine

AA NT

• inhibitory in spinal cord

Epinephrine and Norepinephrine

AA dev NT

• in autonomous NS

  • fight or flight

Dopamine

AA Dev NT in brain

serotonin

AA dev NT in brain

Nitric oxide

gas NT

• relaxation of smooth muscle

  • vasodilation

layers protecting CNS

1. dura mater (many bv)

2. arachnoid mater (collagen web)

   1. cerebrospinal fluid

3. pia mater (directly attaches to CNS)

Forebrain

top/front, largest part

includes the

• cerebrum: cerebral hemispheres. longitudial fissure, corpus callosum

• Cerebral cortex:

  • frontal lobe:

    • prefrontal cortex (decisions)

    • motor cortex (skel muscle)

    • brocas area (speech)

  • parietal lobe

    • somatosensory (temp, touch, pain)

  • occipital lobe

    • visual cortex

  • temporal lobe

    • auditory cortex

    • Wernicke’s area (language)

    • olfactory cortex

• Basal Ganglia (movement and control

• olfactory bulb

• limbic system

  • hypothalamus (hormones, autonomic functions)

  • thalamus (relays with cerebrum)

  • Amygdala (emotions)

  • hippocampus (memory)

Midbrain

connects fore and hindbrain

relays sensory information and reflexes

Hindbrain

cerebellum (balance, coordination)

pons (connects cerebellum and medulla)

medulla oblongata (essential involuntary functions, breathing/heart rate GI activity)

forebrain develops in to

• telencephalon → cerebrum

• diencephalon → thalamus, hypothalamus

midbrain develops into

mesencephalon → brainstem

hindbrain develops into

metencephalon → pons cerebellum

myelencephalon → medulla oblongata

Spinal cord:

afferent nerves arrive through the ____

efferent nerves exit through the ____

afferent: dorsal horn

efferent: ventral horn

PNS

• sensory/afferent:

  • somatic and visceral

• motor/efferent:

  • somatic and autonomic (Sympathetic/fight or flight and parasympathetic/ rest and digest)

vision

rods: night vision, peripheral

cones: color, detail

ear structure

1. outer auricle/pinna and auditory canal

2. middle ear: tympanic membrane, ossicle (malleus, incus, stapes)

3. inner: cochlea (basilar membrane and organ of corti) and semicircular canal

myogenesis

formation of muscle cells

organization of skeletal muscles

muscle covered in epimysium

fascicle covered in perimysium

muscle fiber surrounded by endomysium

myofibril

sarcomere

sarcomere structure

I band: actin only

Z line

A band : entire myosin length

H band : myosin only

type of muscle contractions

concentric: shortens m

eccentric: lengthens

isometric: constant length

muscle types

I : high endurance, aerobic metabolism

IIA: combo of both

IIB: high power, glycolysis

skeletal muscle contraction steps

1. AP down motor neuron to neuromuscular junction

2. Ach released onto motor end plate

3. ligand gates Na+ channels open

4. Na+ enters cells: depolarization

5. AP across sarcolemma and T-Tubul e

6. Voltage gates Ca2+ on SR open

7. Ca2+ exits SR and binds troponin

   1. troponin moves tropomyosin, exposing myosin/actin binding site

sliding filament model

1. troponin moves tropomyosin

2. Cross bridge: ADP and Pi

3. Pi release: power stroke

4. ADP release: rigor

5. new ATP: unbinds crossbridge

6. ATP hydrolyzed: new cross bridge

type of stimuli on muscle

sub-threshold

threshold

sub-maximal

maximal

type of muscle response

simple twitch

temporal summation

tetanus

tonus

types of smooth muscle

single unit: gap junctions, visceral organs

multi-unit: individual innervation, percise control (iris, bronchioles)

membranes covering lungs

parietal pleura: outer

intrapleural space

visceral pleura: inner

larynx

voice box

connects throat to trachea

cough reflex

surfactant

covers alveoli to reduce surface tension that prevents collapse

what brain structure controls respiration

medulla oblongata

• central chemoreceptors sensitive to H+

Fish respiration

countercurrent exchange: water flows over gills perpendicular to blood flow

myoglobin

stores O2 in muscles

Oxygen-Hemoglobin curve

at low PO2 (tissues): oxygen is released from Hb

high PO2 (lungs): Oxygen saturates Hb

Right Shift of oxygen hemoglobin curve

O2 is bound less tightly, high O2 demand

• increase in “CADET”

• CO2

• Acid

• 2.3 DPG

• Exercise

• Temperature

Left shift of oxygen hemoglobin curve

O2 is bound more tightly, less O2 demand

• decrease in CADET

membrane surrounding heart

pericardium, fluid filled sac for protection and lubrication,

pulmonary circulation

right ventricle → pulmonary valve → pulmonary arteries → capillaries → pulmonary veins → left atrium

where is O2 concentration the lowest

pulmonary arteries

systemic circulation

superior and inferior vena cava → right atrium → tricuspid valve → right ventricle → pulmonary circuit → left atria → mitral (bicuspid) valve → left ventricle → aortic valve → aorta → arteries → arterioles → capillaries → venules → veins → vena cava

electrical transmission through the heart

1. SA node (pace maker cells): contract both atria

2. AV node: delay, blood moves into the ventricles

3. Bundle of His: septum between ventricles

4. Purkinje fibers: spreads signal to contract both ventricles

EKG activity

P: atrial contraction

QRS: ventricle contraction

T: ventricle repolarizing

Cardiac output

Stroke volume * heart rate = CO

• CO: blood volume pumped out of heart each minute

• SV: blood volume discharged from ventricles

• HR: heart contractions/ minute

stroke volume

End diastolic volume - End systolic volume = SV

• EDV: blood volume before contraction (full)

• ESV: blood volume after contraction (empty)

Blood Pressure

Cardiac output * systemic vascular resistance = BP

• BP: pressure of circulation blood against the vessels

• SVR: resistance to blood flow, influences by vessel diameter and blood viscosity

  • narrow vessels and thick blood: higher resistance

• CO: blood volume pumped out of heart each minute

main blood vessel controlling blood pressure

arterioles

precapillary sphincter

control blood flow into capillaries

Fetal circulatory and placenta

fetus bypasses liver and lungs because they are not functional yet

placenta:

• maternal (O2) blood → umbilical vein → fetus

• fetal (deO2) blood → umbilical arteries → placenta

fetal circulatory structures

ductus venosus: vessel that bypasses liver

• connects umbilical vein to inferior vena cava

foramen ovale: hole connecting the atria

• R→L atrium to bypass lungs

Ductus Arteriosus: vessel that connects pulmonary artery to aorta

• bypass lungs and heart

blood components

plasma: lowest density. 55%, noncellular

buffy coat: 1% WBC and platelets

hematocrit: 44%, RBC

cells in blood

erythrocytes (RBC)

leukocytes (WBC)

thrombocytes (platelets)

Type A blood has

A antigens on RBC

B antibodies

carbonic acid

ECF buffer

enzyme that converts carbonic acid into water and CO2

blood brain barrier

O2, CO2, lipids can pass

tight junctions and astrocytes

clotting cascade

1. damaged blood vessel exposes collagen

2. collagen attracts platelets

3. platelets release clotting factors

• prothrombin → thrombin

4. thrombin:

• prothrombin → thrombin

• fibrinogen→ fibrin

5. fibrin increases clot

functions of lymphatic system

collects large proteins, particles, and fluid that capillaries cannot take up

screen for pathogens

lymphatic organs

primary: site of lymphocyte formation/maturation

• thymus: T-cell maturation

• bone marrow: blood stem cells

  • leukocytes: all WBC

  • lymphocytes: only B and T cells

secondary: store mature lymphocytes

• lymph nodes: many leukocytes

• spleen many lymphocytes

• adenoids: tonsils

• appendix: on large intestines, vestigial trait

• peyer’s patches: on small intestines

lymphatic ducts

right lymphatic duct: collects lymph from upper right area

• empties into jugular vein

thoracic duct: collects lymph from everywhere else

• empties into the left subclavian vein

lacteals

lymphatic capillaries in the villi of small intestine

• absorb fat

thermoregulation with skin

sweating: evaporative cooling absorbs heat from the body and carries it away

• lose water, electrolytes and ATP

piloerection reflex: goosebumps, traps heat between hair

blood vessels: capillaries constrict when cold

layers of skin

epidermis (no blood, superficial)

dermis (connective, elastic,)

hypodermis (loose connective and adipose tissue)

layers of epidermis

stratum corneum: keratin, hydrophobic

stratum lucidum: palms and soles of feet only

stratum granulosum: keratin, dying keratinocytes and flattening

stratum spinosum: living keratinocytes, flexible

stratum Basale/Germinativum: deepest, melanocytes, Merkel cells, stem cells

cells of epidermis

merkle

Langerhans

melanocytes

keratinocytes

Dermis structure

contains collagen!

corpuscles: mechanoreceptors

• tactile

• lamellar

glands

• sweat/sudoriferous

  • eccrine (everywhere)

  • apocrine (armpit, pubic) onto hair, phermones

• sebaceous/oil

  • sebum onto hair follicles

• ceruminous/wax

  • in ear canal

• mammary/milk

hair

• keratinized cells

innate immune system cells

1st and second line of defense: barriers (physical and chemical) and general, quick response

All have TLR that recognize features of foreign pathogens

• phagocytes, vacuole fuses with lysosomes to breake down endocytosed material

  • neutrophils (most abundant)

  • monocytes, differentiate into macrophages after diapedesis, antigen presenting

  • dendritic cells: antigen presenting

other leukocytes

• eosinophils: against multicellular pathogens

• mast cells: in connective tissue, allergic, inflammatory, anaphylaxis response, release histamine

• basophils: inflammatory response, release histamine

• NK: attack abnormal cells

adaptive immune system

3rd line of defense specific, slow response, memory

• B cells

• T cells: travel to cortex of thymus for positive selection to test MHC binding, then travels to medulla of thymus for negative selection to test if T cells bind too tightly to self-antigens

• and negative selection

• NK cells

• antibodies bind antigen’s epitope

• humoral and cell-mediated response

cytokines

immune signaling molecules

• Interleukin 1: inflammatory response

• Interleukin 2: adaptive response

• Interferons: secreted by infected cell to stimulate other cells to increase defenses

• complement system: inactive → active that forms pores to lyse cell

inflammatory response

increase blood flow to injury to increase WBC

• diapedesis: leukocytes move from blood vessels into tissue

mast cells: secrete histamine

prostaglandins: cause inflammation. fever, pain

Antibody Classes

IgG: most abundant, placenta, Y shaped

IgA: breast milk, mucosa, double Y

IgM: first produced, pentamer

IgE: allergies, Y shaped

Ig: not fully understood, Y shaped

Antibody Structure

glycoproteins

constant region: connected by disulfide bridges

• heavy chain: in center

• light chain:

variable region: on ends, binds epitope

MHC I

glycoproteins of all nucleated cells that present intracellular content

• allows immune cells to detect foreign particles

present to T cells

MHCII

only on antigen presenting cells

• dendritic cells, macrophages, B cells

presents to T cells

Humoral Response

1. B cell binds to antigen → activation and clonal selection and expansion

2. produces plasma (antibodies) and memory B cells

3. memory B cells kept for long term immunity

Function of antibodies

opsonization “tagged”

neutralization (blocks pathogen)

agglutination (clumps pathogens)

enhance other systems (i.e. complement system)

Cell mediated Response

1. T cells in bone marrow

2. recognize MHC and undergo clonal selection and expansion

3. differentiate into

   1. Helper T cells: recognize MHC II and activate other

   2. Cytotoxic killer T cells: recognize MHC I and kill foreign antigens with perforins (trigger apoptosis)

   3. suppressor T cells: negative feedback, prevent autoimmune responses

   4. memory T cell: become helper or cytotoxic T cells upon reinfections

NK cells

detect and kill cells that lack MHC I receptors

• especially tumor cells

innate because they are not antigen specific

adaptive because they induce memory-like functions

immune tolerance

prevents response against self-antigens

• dysfunctional → autoimmune response or immunodeficiency

Acquired Immunity

Active: direct exposure

• natural: pathogen exposure

• artificial: vaccine

Passive: external source

• natural: from mother during development

• artificial: serum (like antivenom)

Antibiotic resistance

overuse of antibiotics: may select for resistance in bacteria and leads to vitamin deficiency

amounts of immune cells

N>L>M>E>B

neutrophils > lymphocytes > monocytes > eosinophils > basophils

peptide hormones and pathways

water soluble, bind to membrane bound receptor

• parathyroid: parathyroid hormone

• pancreas: insulin, glucagon

• Anterior pituitary: prolactin, FSH, LH, ACTH, hGH, TSH

• posterior pituitary: ADH, oxytocin

• secondary messengers: cAMP, IP3, DAG, Calcium

  • cAMP pathway: ligand binds GPCR, G-proteins activates adenylyl cyclase to turn ATP → cAMP which activates PKA

  • IP3 pathway: Ligand binds GPCR, G-protein activates Phospholipase C that cuts PIP3 → IP3 and DAG

    • IP3, not free in cytosol binds to receptor in endoplasmic reticulum and releases Calcium into cytosol that activates other proteins

    • DAG activates PKC

Steroid hormone

cholesterol derivatives, made in smooth ER

• hydrophobic, pass through the membrane, bind to intracellular receptors

• direct stimulation: hormone-receptor complex can act as transcription factor

• adrenal cortex: cortisol, aldosterone

• female gonads: progesterone and estrogen

• male gonads: testosterone

Tyrosine Derivative hormones

Thyroid Hormones: T3, T4

• hydrophobic, bind intracellular receptor

Catecholamines: epinephrine, norepinephrine

• hydrophilic, bind to surface receptor

homeostasis is maintained by

negative feedback loops

endocrine organs

hypothalamus

anterior pituitary

posterior pituitary

pineal gland

thyroid

parathyroid

thymus

adrenal gland

pancreas

testes/ ovaries

hypothalamus

synthesizes oxytocin and ADH → stored in the posterior pituitary gland

• neuronal connection

releases:

• GnRH, CRH, TRH, GHRH, somatostatin, dopamine into the capillary network, then hypophyseal portal veins (vascular connection) transport to anterior pituitary

anterior pituitary gland

anterior pituitary gland activates/inhibits its own hormones

• tropic (indirect)

  • Thyroid stimulating hormone

  • adrenocirticotropic hormone (ACTH)

  • follicle stimulating hormone

    • male: spermatogenesis

    • female: release estrogen

  • luteinizing hormone

    • male: release testosterone

    • female: triggers ovulation, corpus luteum formation

• nontropic (direct)

  • melanocyte stimulating hormone

  • prolactin

  • growth hormone

posterior pituitary

stores ADH (increase water retention) and oxytocin (love hormone)

Pineal gland

secretes melatonin to regulate circadian rhythm