MS-CEM A&P Exam 1

Receptors

Usually transmembrane proteins, very specific regarding binding to messenger (ligand)

Specificity

Receptors ability to bind to single or very limited types of ligands. High specificity limits reactions with other ligands

Affinity

How strongly a receptor binds to ligand

Saturation

Percentage of receptor sites bound by messengers. Percentage of time an individual receptor is bound by a ligand. Concentration+ affinity. Higher saturation= higher activity

Competition

How effectively other similar compounds may be able to bind to same receptor.

Agonist

Competes with normal chemical messenger but triggers the receptor response. Enhances (increases) natural activity

Antagonist

Competes with ligand but does not trigger response. Blocks the signal transduction.

Downregulation

Decrease in number of receptors. Typically in response to high concentration of messenger.

Upregulation

Increase in receptors

Signal transduction pathways

Binding of ligand leads to conformational change (receptor activation). Signal transduction pathway is activated —> leads to cell response.

Allosteric modulation

Noncovalent binding changes protein shape.

Functional site

Where ligand binds. May alter other functional sites- cooperativity

Regulator site

Binding changes shape of functional site. Can “turn on” or “turn off” functional site. Alters affinity of functional site to ligand

Covalent modulation

Binding charged groups to receptor (on/off switch). Changes electrical distribution, change in conformation. Ex: phosphorylation

Lipid soluble messengers

Able to penetrate membrane. Receptors usually in the nucleus. Binding leads to gene transcription/ protein synthesis (or possibly inhibition)

Water soluble messengers

Binds at membrane. Receptor activation may yield second messenger inside cell, which enacts response.

Receptor as ion channel

Activated by ligand, conformational change opens ion channel —> ions move by diffusion

Receptor which acts as enzyme

Receptor had protein kinase activity (usually tyrosine kinases) —> ligand binding activates enzymatic portion. Creates cascade of events which leads to desired response.

Interaction with cytoplasmic kinases

Receptor does not directly have enzyme (kinase) activity. Targets proteins TFs resulting in protein synthesis.

JAKs

Cytoplasmic tyrosine kinases.

G-protein coupled receptors

G proteins

Complex with 3 subunits- alpha, beta, gamma

Second messenger- cAMP

Specific second messenger for G protein pathway. Converts ATP to cAMP —> cAMP dependent protein kinase —> cell response

Signal amplification

One messenger can lead to potentially millions of product molecules

Second messenger- Calcium

Very low intracellular concentration due to active transport. Voltage gated channels

Arachadonic acid —> cycloogygenase

Cyclic endoperoxides. Vascular and inflammatory action. Blood clotting

Arachadonic acid —> lipoxygenesase

Leuktrienes. Allergic/ inflammatory response. (Respiratory)

Anatomy

The study of the structures, shape and form of the parts of the human body (morphology) and their relative arrangement

Physiology

Study of the function of body parts “what they do and how they do it”

Functional role

The “jobs” a part does in the body (may be more than one)

“Form follows function”

Over many generations parts evolve to perform their functions more efficiently

Pathology

Abnormalities/ disruptions of A&P that lead to disease

Homeostasis

Maintenance of a stable internal environment

Normal range

Homeostatic mechanism keep values in a normal range

Dynamic consistency

Short term variations “average out” to consistent long-term stability

Steady state

Set point is maintained, but energy is required

Negative feedback

Most common regulation system. As conditions deviate from set point, effectors are activated. As conditions get closer to normal, signal to effectors gradually decreases

Positive feedback

Homeostatic change occurs, response initiated. End product stimulates continuation of response

Feedforward regulation

Sensors note a change that likely will affect set point. The body responds by making changes in anticipation before change actually occurs. Minimizes effect if stimulus and deviation.

Intercellular messengers

Hormones, neurotransmitters, paracrine, autocrine, juxtracrine, gap junctions

Paracrine agents

Act on local cells

Autocrine agents

Act on secreting cell. Ex: monocytes

Juxtracrine

Surface proteins —> growth, differentiation, barriers, tissue formation

Adaption

Presence of a characteristic increasing survival in specific environments

Acclimation

Improvement of adaption with exposure

Sagittal plane

Divides body into right and left

Transverse (horizontal) plane

Divides the body into superior and inferior

Coronal (frontal) plane

Divides the body into anterior and posterior

Abdominal

Region between thorax and pelvis

Acromial

Point of the shoulder

Antebrachial

Forearm

Anticubital

Anterior surface of elbow

Axillary

Armpit

Brachial

Arm

Buccal

Cheek

Carpal

Wrist

Celiac

Abdomen

Cephalic

Head

Cervical

Neck

Costal

Ribs

Coxal

Hip

Crural

Leg

Cubical

Elbow

Digital

Finger/toe

Dorsal

Back

Femoral

Thigh

Frontal

Forehead

Genital

External reproductive organs

Gluteal

Buttocks

Inguinal

Groin

Lumbar

Lower back

Mammary

Breast

Mental

Chin

Nasal

Nose

Occipital

Posterior region of head

Oral

Mouth

Orbital

Eye cavity

Otic

Ear

Palmar

Palm of hand

Patellar

Anterior part of knee

Pectoral

Anterior chest

Pedal

Foot

Pelvic

Pelvis

Perineal

Inferior region of trunk between thighs and buttocks

Plantar

Sole of foot

Popliteal

Posterior area of knee

Sacral

Posterior region between hip bones

Sternal

Anterior center of thorax

Sural

Calf

Tarsal

Ankle

Umbilical

Navel

Vertebral

Spinal column

Superior

Above

Inferior

Below

Anterior

In front of

Posterior

Behind

Medial

Towards the midline

Lateral

Away from midline

Proximal

Close to center (or point of attachment)

Distal

Far from center (or point of attachment)