Body systems

2 constituents of total body water

• intracellular fluid

• extracellular fluid

3 constituents of extracellular fluid

• interstitial fluid

• plasma

• transcellular fluid

4 basic tissue types

• Epithelial

• Muscle

• Connective tissue

• Nervous

examples of transcellular fluid

• cerebrospinal fluid

• urine

• gastrointestinal secretions

• sweat

• synovial fluid

intracellular fluid (IFC)

all water inside of cells

extracellular fluid (EFC)

all water outside of cells

interstitial fluid

fluid outside of vessels

functions of transport proteins

• exporting waste from cells

• uptake of nutrients, substrates and co-factors

• regulation of ions, pH and volume of cells

• asymmetric distribution of ions to create membrane potential

homeostasis

continuous physiological process which establishes a relatively stable internal environment

autoregulation

homeostasis enacted by processes within a cell or tissue

extrinsic regulation

a process which results from the activities of the nervous or endocrine system

negative feedback

aims to maintain a controlled variable at its set point

afferent pathway

pathway leading TOWARDS the central nervous system

efferent pathway

pathway leading away from the central nervous system

positive feedback

initial stimulus causes a response which enforces itself

ganglia

clusters of nerve cell bodies that act as relay stations in the peripheral nervous system

autonomic effects on pupils

Sympathetic dilates pupils; parasympathetic constricts pupils

fibre lengths in sympathetic nervous system

Short preganglionic fibre and long postganglionic fibre

fibre lengths in parasympathetic nervous system

Long preganglionic fibre and short postganglionic fibre

ganglionic transmitter in autonomic nervous system

ACh

sympathetic neurotransmitter

Noradrenaline (NA)

parasympathetic neurotransmitter

ACh

sympathetic nervous system function

Fight or flight

parasympathetic nervous system function

Rest and digest

locations of epithelial tissue

• Covers surfaces

• Lines cavities and tubes

• Forms glands

4 main characteristics of epithelial tissue

• Attachment to a basement membrane

• Avascularity (no blood supply; receives $O_2$ via diffusion)

• Regeneration

• Polarity (exposed apical surface and attached basal surface)

simple squamous epithelium

• Structure: Single layer of flat cells with oval nuclei

• Function: Exchange of nutrients and gases

• Locations: Blood vessels, alveoli

non-keratinised stratified squamous epithelium

• Structure: Multiple layers of flat cells with oval nuclei

• Function: Protection / barrier

• Locations: Oral cavity, oesophagus

keratinised stratified squamous epithelium

• Structure: Multiple layers of flat surface cells; upper layers consist of dead, keratin-filled cells lacking nuclei

• Function: Waterproofing, physical barrier

• Locations: Skin

simple cuboidal epithelium

• Structure: Single layer of square cells with round nuclei

• Function: Secretion and absorption

• Locations: Glands, kidney tubules

simple columnar epithelium

• Structure: Single layer of tall cells with oval, basally located nuclei; contains surface microvilli

• Function: Absorption and secretion

• Locations: Gastrointestinal tract

pseudostratified ciliated columnar epithelium

• Structure: Tall cells with basally located nuclei; all cells contact the basement membrane but not all reach the apical surface; contains cilia and goblet cells

• Function: Creates mucociliary escalator protecting lungs

• Locations: Trachea, large respiratory airways

desmosomes

• very strong

• between adjacent cells

• resists stretching and twitching

hemidesmosomes

• attach cells to basement membrane

• stabilises their position

• anchors cells to underlying membrance

tight junctions

• interlocking proteins

• bind cells together near apical edge

• prevents passage of water and solutes between cells

• in digestive tract

gap junctions

• interlocking membrane proteins with central pore

• allows movement of small molecules and ions between cells

• found in cardiac muscle

types of intercellular junction

• desmosomes

• hemidesmosomes

• tight junctions

• gap junctions

connective tissue

cells within an extracellular matrix. supports, protects, binds, and gives structure to other tissues and organs in the body

examples of specialised connective tissue

• blood

• bone

• cartilage

connective tissue proper

all major types of connective tissue excluding specialised connective tissue (blood, bone and cartilage). Made of:

• loose areolar

• dense areolar

• dense irregular

loose areolar connective tissue

found under epithelium lining body surfaces

what does loose areolar contain?

• lots of ground substance

• few fibres

• variety of cells (fibroblasts, adipocytes, macrophages)

dense irregular connective tissue

found in the dermis, made to resist stretching and distention

what does dense irregular connective tissue contain

• little ground substance

• many collagen fibres arranged randomly

• few cells, mainly fibroblasts

dense regular connective tissue

found in tendons & ligaments, provides high tensile strength

what does dense regular connective tissue contain

• very little ground substance

• many densely packed bundles of of collagen fibres in parallel rows

• few cells (mainly fibroblasts)

how is connective tissue proper classified

according to type, arrangement & abundance of fibres, cells & ground substance

how are cardiac muscle cells connected to eachother

gap junctions

tunica intima

• inner most layer of a blood vessel

• simple squamous endothelium and basal lamina

• subendothelial connective tissue

tunica media

• middle layer of a blood vessel

• made of smooth muscle fibres and loose connective tissue

• sometimes elastic fibres

tunica externa

• outermost layer of blood vessel wall

• connective tissue

• merges with surrounding connective tissue

types of arteries

• elastic / conducting arteries

• muscular / distributing arteries

• arterioles (resistance vessels)

elastic arteries structure

• large

• thick tunica media (withstand pressure)

• many elastic fibres

elastic arteries function

transports large volumes of high pressure blood away from heart. ensures continuous blood flow

examples of elastic arteries

• aorta

• brachiocephalic

• common carotid

muscular artery structure

• smaller than elastic

• smooth muscle in tunica media

• internal and external laminae

• thick tunica externa

muscular artery function

• delivers blood from elastic artery to muscles and organs

• vasodilates and constricts to control blood flow to suit the need of the organ

muscular artery examples

• femoral

• brachial

arteriole structure

• 1-2 layers of smooth muscle cells in the tunica media

• poorly defined tunica externa

arteriole function

• delivers blood into capillaries

• part of peripheral vascular system

• vasoconstriction and dilation to control blood flow and bp

types of capillaries

• continuous

• fenestrated

• sinusoidal

continuous capillaries - where?

• found in skeletal, smooth muscle, connective tissue and the lungs

continuous capillaries

allow for exchange between capillaries and adjacent cells, with an uninterrupted lining joined by tight junctions

fenestrated capillaries

the endothelial lining is porous, allows for rapid exchange of water and large solutes. specialised for absorption.

fenestrated capillaries - where?

kidneys and endocrine glands

sinusoidal capillaries

capillaries with an incomplete basement membrane, so very permeable, allowing for large solutes to move though easily

sinusoidal capillaries - where?

specialised linings, eg liver

main structures in a capillary bed

• metarterioles

• precapillary sphincter

• arteriovenous anastomoses

metarterioles

a short micro-vessel in the circulatory system that connects arterioles to capillaries to venules. By contracting, can reduce blood flow to the capillary bed

precapillary sphincter

a band of contractile muscles at the entrance to each capillary. Vasoconstricts and dilates to control blood flow

arteriovenous anastomoses

direct, low-resistance connection between an arteriole and a small venule that bypasses the capillary bed. Dilation allows blood to bypass the capillary bed and drains directly into the venous circulation

anatomical directions

• medial

• lateral

• superior

• inferior

• proximal

• distal

medial direction

towards the centre of the body

lateral direction

away from the centre of the body

superior direction

upwards towards the sky

inferior direction

towards the ground

proximal direction

pointing closer to the trunk

distal direction

pointing away from the trunk

anatomical planes

• sagittal plane

• transverse plane

• coronal plane

sagittal plane

splits the body into left and right sides

transverse plane

splits body into lower and upper sections

coronal plane

splits body into the front and back

layers covering the heart

• fibrous pericardium

• serous pericardium

• parietal layer

• visceral layer

• pericardial cavity

fibrous pericardium

made of a dense connective tissue which fuses with the diaphragm and great vessels and prevents overfilling of the heart and anchors it in position

serous pericardium

a double layered serous membrane which lubricates the heart and allows for smooth movement

parietal layer

lines the inner surface of the fibrous pericardium

visceral layer

adheres to the surface of the heart

pericardial cavity

potential space between the parietal and visceral layers, contains pericardial fluid

layers of the heart wall

• endocardium- aka visceral layer

• myocardium

• epicardium

endocardium

innermost layer, the simple squamous layer with underlying connective tissue

myocardium

middle layer, made of cardiac muscle

epicardium

the outer layer, aka the visceral pericardium

angiography

a technique for examining the patency (open-ness) of coronary vessels

tricuspid valve

right AV valve

bicuspid valve

left AV valve

ductus arteriosus

A blood vessel in foetuses which connects the pulmonary artery and aorta, bypassing the lungs.

foramen ovale

an interatrial opening in foetuses which allows blood to flow straight from the right to left artery, bypassing the lungs

haematopoiesis meaning

the formation of red blood cells

hemocytoblasts

multipotent haematopoietic stem cells found in red bone marrow, which differentiates into blood cells

myeloid stem cells differentiate into:

• erythrocytes

• macrophages

• mast cells

• neutrophils & other granulocytes