SKIN AND BODY MEMBRANES

Epithelial Membranes

•The cutaneous membrane is the:

•Mucous membranes

•Mucosae

• (e.g., digestive and respiratory tracts)

•Serous Membranes

•Paired membranes that line:

•Parietal layer -

•Visceral layer –

• Serous Membranes are named based on their location:

•Parietal and visceral pleura surround:

•Parietal and visceral pericardium surround:

•Parietal and visceral peritoneum surround:

Skin (Integument)

•Consists of three major regions

1.Epidermis—

2.Dermis—

3.Hypodermis (superficial fascia)—

•

Epidermis

•

•Cells of epidermis

•Keratinocytes—

•Melanocytes

•

Layers of the Epidermis: Stratum Basale

•

•Also called stratum germinativum:

•Cells travel from basal layer to surface

•Takes 25–45 days

Layers of the Epidermis: Stratum Spinosum

•

•

Layers of the Epidermis: Stratum Granulosum

•

•

Layers of the Epidermis: Stratum Lucidum

•

•

•

Layers of the Epidermis: Stratum Corneum

•

•

•Functions

•

•

Dermis

•Made up of Twolayers:

•Papillary layer

•Reticular layer

Layers of the Dermis: Papillary Layer

•Papillary layer

•Composed of:

•Contains dermal papillae which may have:

•
•
•

Layers of the Dermis: Reticular Layer

•Reticular layer

•Composed of:

•

Skin Color

•Three pigments contribute to skin color:

1.Melanin

•

•

2.Carotene

•

3.Hemoglobin

•

Appendages of the Skin

•Derived from the epidermis

•

•

•

•

Sweat Glands

•Two main types of sweat (sudoriferous) glands

1.Eccrine sweat glands— abundant on palms, soles, and forehead

•Sweat:
•
•

2.Apocrine sweat glands—confined to:

•Sebum:
•
•

Sebaceous (Oil) Glands

•

•

•

•Sebum

•

•

•

Hair

•Functions

•

•

•Consists of:

Hair Follicle

•Two-layered wall consisting of:

•Hair bulb:

•Hair follicle receptor (root hair plexus):

•

•Arrector pili

•

•

Structure of a Nail

•

•Structures of the nail:

Functions of the Integumentary System

1.Protection—

•Chemical

•

•Physical/mechanical barriers

•

•

•Biological barriers

•

2.Body temperature regulation

•

•

3.Cutaneous sensations

•

4.Metabolic functions

•

•

5.Blood reservoir—

6.Excretion—

Skin Cancer

•Three major types:

•Basal cell carcinoma

•Squamous cell carcinoma

•Melanoma

Basal Cell Carcinoma

•

•Appearance:

•

•

Squamous Cell Carcinoma

•

•Appearance:

•

Melanoma

•

•Appearance:

•

•

Melanoma

•Characteristics (ABCDE rule)

A: Asymmetry-

B: Border-

C: Color-

D: Diameter-

E: Evolution-

Partial-Thickness Burns

•First degree

•

•

•Second degree

•

•

Full-Thickness Burns

•Third degree

•

•

•

•

THE CARDIOVASCULAR SYSTEM

Heart Anatomy

•Approximately the size of a fist

•Location

•

•

•

•Enclosed in pericardium, a double-walled sac

Pericardium

•Superficial fibrous pericardium

•

•Deep two-layered serous pericardium

•Parietal layer lines:

•Visceral layer (epicardium) is on :

•Separated by fluid-filled pericardial cavity (decreases friction)

Layers of the Heart Wall

1.Epicardium =

2.Myocardium

•

3.Endocardium

Chambers

•Four chambers

•Two atria

•

•Separated internally by:

•Two ventricles

•

•Separated internally by:

Major Blood Vessels of the Heart

•Vessels entering right atrium

•

•

•

•Vessels entering left atrium

•

•Vessel leaving the right ventricle

•

•Vessel leaving the left ventricle

•

Pathway of Blood Through the Heart

•The heart is two side-by-side pumps

•Right side is the pump for the pulmonary circuit

•

•Left side is the pump for the systemic circuit

•

•Right atrium  tricuspid valve  right ventricle

Right ventricle  pulmonary semilunar valve  pulmonary trunk  pulmonary arteries  lungs

Lungs  pulmonary veins  left atrium

Left atrium  bicuspid valve  left ventricle

Left ventricle  aortic semilunar valve  aorta

Aorta  systemic circulation

•Anatomy of the ventricles reflects differences in pulmonary and systemic circuits

Coronary Circulation

•

•Arteries

•

•

•Veins

•

Homeostatic Imbalances

•Angina pectoris

•

•Myocardial infarction (heart attack)

•

•

Heart Valves

•Ensure unidirectional blood flow through the heart

•Atrioventricular (AV) valves

•

•

•

•Chordae tendineae anchor AV valve cusps to papillary muscles

•Semilunar (SL) valves

•

•

•

Microscopic Anatomy of Cardiac Muscle

•

•

•

•

•Intercalated discs: junctions between cells anchor cardiac cells

•Desmosomes prevent :

•Gap junctions allow :

•Heart muscle behaves as a functional syncytium

Heart Physiology: Electrical Events

•Intrinsic cardiac conduction system

•Defined:

Autorhythmic Cells

•

•

Heart Physiology: Sequence of Excitation

1.Sinoatrial (SA) node (pacemaker)

•

•

2.Atrioventricular (AV) node

•

•

•

3.Atrioventricular (AV) bundle (bundle of His)

•

4.Right and left bundle branches

•

5.Purkinje fibers

•

•

Homeostatic Imbalances

• Defects in the intrinsic conduction system may result in

1.Arrhythmias:

2. Fibrillation: rapid, irregular contractions; useless for pumping blood

•Defective AV node may result in

•

•

Extrinsic Innervation of the Heart

•

•Cardiac centers are located in the medulla oblongata

•Cardioacceleratory center innervates:

•Cardioinhibitory center inhibits:

Electrocardiography

•Electrocardiogram (ECG or EKG): a composite of all the action potentials generated by nodal and contractile cells at a given time

•Three waves

1.P wave:

2.QRS complex:

3.T wave:

Mechanical Events: The Cardiac Cycle

•Cardiac cycle: all events associated with blood flow through the heart during one complete heartbeat

•Systole—

•Diastole—

Cardiac Output (CO)

•

•CO = heart rate (HR) x stroke volume (SV)

•HR =

•SV =

Cardiac Output (CO)

•At rest

•CO (ml/min) = HR (75 beats/min)  SV (70 ml/beat)

= 5.25 L/min

•Maximal CO is 4–5 times resting CO in nonathletic people

•Maximal CO may reach 35L/min in trained athletes

Homeostatic Imbalances

•Tachycardia: abnormally fast heart rate (>100bpm)

•

•Bradycardia: heart rate slower than 60bpm

•

Developmental Aspects of the Heart

•Fetal heart structures that bypass pulmonary circulation

•

•

BLOOD VESSEL PHISIOLOGY

Blood Vessels

  • Arteries:
  • Capillaries:
  • Veins:

Structure of Blood Vessel Walls

  • Arteries and veins
  • Tunica intima –
  • Tunica media -
  • Tunica externa -
  • Lumen
  • Capillaries
  • Functions:

Capillary Exchange of Respiratory Gases and Nutrients

  • Diffusion of

Hydrostatic Pressures

  • Capillary hydrostatic pressure (HPc) (capillary blood pressure)

Osmotic Pressures

  • Capillary oncotic pressure (OPc)
  • Created by:

Arteries to Know:

  • Aorta
  • Coronary arteries
  • Subclavian arteries (what is the difference btwn. Left and right subclavian arteries in terms of how they branch)
  • Brachiocephalic trunk
  • Axillary artery
  • Brachial artery
  • Radial and ulnar artery
  • Palmar arch and digital arteries
  • Celiac trunk (foregut)
  • Common hepatic
  • Left gastric
  • splenic
  • Superior mesenteric artery (midgut)
  • Inferior mesenteric artery (hindgut)
  • Hepatic portal system
  • Splenic vein and superior mesenteric vein are final tributaries to the hepatic portal vein
  • Blood is drained from liver via hepatic veins into inferior vena cava to right atrium of heart

1