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anatomy and physiology

anatomy is the study of internal and external body structures, it focuses on location, structure and the relationship between body parts. Human anatomy can be divided into gross anatomy and microscopic anatomy. Click the images to learn more about each.

what is anatomy

A physisian will use a range of techniques to assess a person. looking at anatomical, chemical and psychological signs and symptoms as well as physiological ones.

what is physiology

Physiology asks how function happen, what makes us work? These functions ar emore complex than simply studying anatomy and so there are more divisions of the study.cellular physiologyorgan physiologysystemic physiologypathological physiology

tissue level

when a group of cells come together to preform specific functions this is know as a tissue which is then studdied at this level.

cellular level

individual cells are made of several organelles, each of which playing a part to ensure the cell functions correctly.

chemical level

the shape of molecules is often very complex, and even small changes affect the function. This is seen clearly in proteins where the shape of the molecules affect the active site of the protein

levels of understanding/organisation

two or more tissues working together for a specific function is considered an organ like the lungs or the liver.

groups of organs can then come together and interact. This is an organ system, like the cardiovascular system.

The human as a whole individual life form is the organism. All previous levels must be fully functioning for the organism to be healthy.

organism level

organ system level

levels of understanding/organisation

organ level

body fluids and membrane transport

  • made of a phospholipid bilayer with proteins intersperced within, around 5nm thick
  • many proteins to regulate movement of solutes and help control intracellular environment. Maintainence includes uptake of nutrients, exporting waste, regulating ions, pH, cell volume, p.d. and osmolality
  • Channel proteins allow a type of molecule to undergo facilitated diffusion straight into or out of the cell down their concentration gradient
  • carrier proteins also move molecules down their concentration gradient but in three different ways. Faciliatator/uniport poriens change shape to allow one molecules to travel in one direction. Cotransporters/symport proteins allow two different molecules to move in one direction. Exchangers or antiport proteins move two different molecules in two different directions
  • Pumps require energy to actively transport one molecule at a time against their concentration gradient.

plasma membrane

water distribution between the ISF and the plasma is decided by two kinds of pressure. Hydrostatic pressure would have water moving out to the ISF, but the osmotic attractiveness of proteins stuck in the plasma means the colloid osmotic pressure has water moving into the plasma

small ions and organic solutes are approximately equal concentrations in the ISF in comparison to the blood plasma, but there are far more proteins in the plasma because theyre to big to cross the basement membrane.

regulation of pressure and osmolality

ion and protien regulation


- very thin layer of cells- hihgly permeable (leaky) in most areas of the body, the brain is an exception- basement membrane acts as a filter- regulates the interstitial fluid

capillary endothelium


epithelial cells are found covering both the internal and external surfaces of organs and tissues. They act as a protective barrier controlling what is absorbed and what is secreted. They are well suited for this role due to the tight junctions between cells and the abundance of transporter proteins. The apical membrane is the side facing into a lumen and the basolateral membrane is the opposite.

the regulation of a consistant internal enviroment through feedback loops


positive vs negative feedback

there are two types of feedback loops which help maintain homeostasis:

positive feedback is rarer because it requires an external stimuli to end. The increase of a molecule eventually causes its own increase

positive feedback

negative feedback

maintains a variable around a set point. The increase of one molecule eventually causes a decrease of the same molecule

control systems

There are two main control systems in the human body. The endocrine system relies on hormones, it is a slower change system resulting in long term effects. The nervous system uses electrochemical signals to send more immediate and short term changes.

the nervous system is separated into several divisions.

nervous system

Epithelial cells





epithelia cell basics

epithelia cover surfaces and line tubes and cavities, they also form glands. This means that they protect areas, control permeability and sometimes provide sensation. Cilia are classified through their shape and the number of cell layers in the most superficial level. Overall there are four important characteristics of epithelium cells:

classifications of epithelial cells

intercellular juntions

gap junctions

tight junctions



connexons (proteins) hold cells together but have a small passageway in them allowing the movement of small molecules and ions

on the exposed (apical) side of the cell, cell membranes are bound together by proteins.

anchor the cell in position by binding to the basement membrane

strong connections joing adjacent cells, desmosomes are resistant to twisting and stretching.

connective tissue consists of cells within an extracellular matrix. Fibroplasts are the cells which synthesise this matrix which is made of ground substance, tissue fluid and fibres. The function of this tissue includes providing framework, transporting fluids and solutes, protecting organs and storing energy in the form of triglycerides.

connective tissue

specialised connective tissue




loose (areolar) connective tissue

areolar tissues is the least specialised kind of connective tissue proper. It has an open framework. It has a variety of cells but ground substance provides most of the volume, it also absorbs shock. This tissue forms a layer separating the skin from deeper structures. Its loose structure allows for distortion without damage and elastic fibres allow it to have lots of independant movement.

dense irregular connective tissue

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Alayer of this connective tissue gives the dermis its strength, this is because there is little ground substance but lots of haphazardly arranged collagen fibre bundles. It is also resistant to stretching and distentsion which is why it form protective capsules around organs like the kidneys

dense regular arranged connective tissue

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collagen fibres arranged in regular parallel rows make up the majority of the volume of this tissue. This means there is little ground solution and few cells. This type of tissue is found in tendons and ligaments

Muscle tissue produces movement as it is specialised for contraction. There are 3 types of muscle tissue but all have contractile elements, many mitochondrion and they are all elongated parallel to the axis of contractions

muscle tissue

types of muscle tissue

cardiac muscle

  • found in heart wall
  • helps circulate blood and maintain bp
  • branched fibres
  • striated
  • 1/2 central nuclei
  • intercalculated discs

smooth muscle

  • found in the walls of organs, blood vessels and airways
  • controls GI movement
  • alters diameter of airways and blood vessels
  • short, spindle shaped cells
  • single centrally located nucleus

skeletal muscle

  • moves and stabilises the skeleton
  • forms sphincters in the digestive and urinary tracts
  • is involved in respiration
  • long, cylindrical cells
  • striated
  • multinucleated
keratinised stratified squamous

Flat surface, oval shaped nuclues, many layers, keratin, function = protective, waterproof barrier, location = skin

simple squamous

  • Flat cells
  • oval shaped nuclie in thickest part of cell
  • major function = the exchange of gases and nutrients
  • location = blood vessels and alveoli

Gross anatomy studies larger structures and therefore does not need a microscope. There are several catagories of gross anatomy, some are listed below:

Gross anatomy

study of larger structures
  • surface anatomy (body surface)
  • regional anatomy (head, trunk, legs etc)
  • sectional (uses cross sections of prgans and tissues)
  • systemic (studies organ systems like cardiovascular or skeletal)
  • square cells
  • round nuclei
  • one layer
  • major function = secretion and absorbtion
  • location = kidney tubules and glands
simple cuboidal
  • tall cells
  • appears tratified as some dont reach free surface
  • modifications = cilia and goblet cells
  • function = mucociliary escalator
  • location = trachea and large respiritory airways
psuedostratified ciliated columnar cells with goblet cells
  • tall cells
  • basally located, oval nuclei
  • major function = absorbtion and secretion
  • location = GI tract
  • Surface adaptation = microvilli
simple columnar
  • flat surface cells with oval shaped nuclie
  • many layer
  • major function = protection, barrier
  • location = oral cavity, oesophagus
non-keratinised stratified squamous
  • histology, is the study of tissues (groups of cells)
  • cytology studies individual cells

Studying some areas of anatomy requires microscopes. This study is split into two areas.


fight or flight

the sympathetic nervous system is associated with a state of flight or fight. It sends signals to increase heart rate, increase breathing rate, slow digestion etc. The eurons flow from the thoracic and lumbar section of the spine.

  • short preganglionic fibres
  • transmits ACh at the ganglion
  • long postganglionic fibres
  • transmits norepinephrine at the effector


rest and digest

the parasympathetic nervous system is associated with a bodily state of rest, this means this it sends signals to lower heart rate, increase digestion rate and so on. Neurons in the parasympathetic nervous system stem from the cranial and sacral part of the spine

  • long preganglionic neurons
  • transmits ACh at the ganglion
  • short post ganglionic neuron
  • transmits ACh to the effector