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Anatomy Anatomy is the classification and description of the structures of the body and the science concerned with the physical structure of animals and plants. Conducting an 'anatomy' involves dissection of a plant or animal to study the structure, position, and interrelation of it's various parts. Modern anatomy can be implemented into everyday life. •

For example with the understanding of the anatomy of the gecko hand and filament was on the gecko skin that allowed it to stick to even the smoothest of surfaces. This created model to produce some superglues.

Relationship Between Form and Function Morphological features like tail length, incisor size or finger length can give indications of the behaviour of the animal. •

Aye-aye use their large eyes, big ears and long middle fingers in tandem with each other for predatory purposes. Their eyes help them as they are nocturnal, their long middle fingers is used to tap tree trunks where their prey resides and their large ears are used to listen for these vibrations.

However sometimes form and function doesn’t work. •

The ibok, whose hooves aid it to climb essentially vertical walls to get food. In today’s modern world, these animals climb structures like dams thus risking their life.

Divisions of Anatomy Anatomy is studied mainly at 2 scales, microscopic and gross anatomy. Microscopic Anatomy •

considers structures that are too small to be seen by the naked eye. This includes cytology (analysis of the internal structure of cells) and histology (study of tissues)

Gross Anatomy •

macroscopic or topographical anatomy considers relatively large structures and features visible to the naked eye. This includes Surface Anatomy, Regional Anatomy, Systemic Anatomy and Developmental Anatomy o Surface Anatomy- surface landmarks which correspond to deeper structures hidden from view o Radiology- branch of medical science dealing with the use of medical imaging to diagnose and treat disease

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Comparative Anatomy- considers the anatomical organisations of different types of animals

Systemic Anatomy- considers the organisation of body into systems that work together to carry out complex functions. Regional Anatomy- focuses on the anatomical organisation of specific areas of the body, such as the head, the neck, or trunk. This approach emphasises the spatial relationships among structures.

Biological concept of adaptation •

generally defined as the ability of an organism to survive and produce in it's environment. An adaptation can structural or behavioural like migration.

What causes adaptation in humans is human variation which essentially allows adaptation to environmental conditions. Physiological responses to the environment operate at two levels: 1. Long Term Adaptation o This is genetic change. When an evolutionary change occurs characterising all individuals within a population or species 2. Short Term Adaptation o Temporary physiological responses such as acclimatisation Vestigial Structures are traits that have been lost or reduced their function as they are no longer useful or advantageous to the animal like the hind legs of a whale.

Homology vs Analogy Homologous structures are structures that are similar in their fundamental construction, although they may serve different purposes. •

For example, the human arm, bat wings, whale flippers, dog legs are all homologous structures

Analogous structures are different and arise from convergent evolution. This is when functions of structures of the same but there is structural difference due to the lack of common ancestral origin. •

Flying fox wings and bird wings are analogous as their structures are different

The Skeletal System The Human Skeleton ( Function and components) The human skeleton has multiple functions including: 1. 2. 3. 4. 5.

Support Protection of organs Movement (through muscular attachment) Blood cell production Storage for nutrients (e.g Ca+)

The components of the skeleton -

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Bones o Osseous tissue like specialised cells (osteoclasts, osteoclasts) and mineralised matrix Cartilage o Connective tissue with gelatinous matrix Joints o Area where adjacent bones interact Ligaments o Dense bands of connective tissue that attach bones to each other

The proximal end of the Humerus On the end is articular cartilage o

Articular cartilage provides smooth, low friction, gliding surface for movement

On the outside of the bone is periosteum o

This is a fibrous connective tissue sleeve that covers the bone

On the outermost inside layer of the bone is cortical or compact bone o

Solid dense bone of well vascularised calcified tissue

On the inside is trabecular bone This is spongey bone and is composed of a network of bony struts or mineralised trabeculae tissue with little to no blood vessels o Surrounds marrow or adipose tissue. o

On the very inside of the bone is bone marrow.

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This fills the medullary cavities in bones and contains red marrow which produces RBC and yellow marrow which is adipose tissue

Tissue: Bones, cartilage and ligaments Bone There are 4 physical pressures that cause directional pressure on bones and the human skeleton has evolved to resists these forces. These forces include compression, tension, shear and torsion. The tension and compression forces especially have driven the formation of the trabecular bone along pressure lines. Cartilage cartilage is independent tissue than bone and contain chondrocytes and ECM with carrying densities of collagen It is resilient, semi rigid form of dense CT that is ... • • •

resistant to compressive forces found where more flexibility is required covers the articulating surfaces of bone

Cartilage is avascular and thus receives it's nutrients and oxygen via diffusion. This is why cartilage requires a-lot longer to heal if damage occurs Types of cartilage Hyaline cartilages • • • •

ECM contains closely packed collagen fibres supports tissue and organs and is a model for bone development in adolescence Found in areas to reduce friction and permit movement (articular surface) e.g joints. costal cartilage, nose tip

Elastic Cartilage • • • •

Matrix contains numerous elastic fibres Extremely resilient and flexible Found in areas that are soft but need to hold their shape e.g ears and throat

Fibrocartilage •

Matrix is dominated by densely interwoven collagen fibres

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Extremely durable and tough found joining bones within a joint cavity e.g meniscus of the knee, pubic symphysis and intervertebral discs

Ligaments Ligaments are dense CT that connect one bone to another that support, strengthen and reinforce joints. They are comprised of collagen fibres that are long, straight(unbranched) and arranged into fibrous subunits wound together like the strands of a rope. Ligaments are flexible but can withstand large forces especially strong when pulled end to end due to the way the fibres are organised. The ligament fibres run in line with the tensions along the ligament to restrict joint separation. Uncontrolled movements are likely to break a bone more than snapping ligaments.

Bones of the Skeleton (divisions and regions) The human skeleton is made of 206 bones and thus needs to be sorted into divisions and regions. The divisions include the Axial Skeleton(80 bones) and the Appendicular skeleton (126 bones).The regions of the skeleton are smaller subdivisions like the thorax and the hand and tends to be separated by major joints. Axial Skeleton •

This division is 3 regions o the Skull, the Vertebral column and the Thoracic cage. § The Skull is comprised of the cranial bones and the mandible. § The vertebral column of the cervical, thoracic, lumbar, sacrum and coccyx regions. § The Thoracic cage of the ribs (costal bones) and sternum

Appendicular Skeleton • •

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Composed of the Upper and Lower Limbs The Upper limb is comprised of 4 regions o the Pectoral girdle, the Arm, the Forearm and the Hand § The Pectoral girdle is the Scapula and Clavicle § The arm is the Humerus § The Forearm is the Radius and the Ulna § The Hand is made up of the Carpal bones, Metacarpal bones and Phalanges. The Lower Limb is divided into 5 regions

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the pelvic girdle, the Thigh, the Knee, the Leg and the Foot. § The Pelvic girdle is comprised of the Pelvis and the Proximal Femur § The Thighs is made up of the Femur § The Knee is made up of the distal Femur, the Patella, the Proximal Tibia and the Proximal Fibula § The Leg is comprised of the Tibia and the Fibula § The Foot is made up of the Tarsal bones, metatarsal bones phalanges

Classification of bones Bones are classified by their shape into 5 categories: Long bones, Short Bones, Flat Bones, Irregular Bones and Sesamoid Bones Long Bones -

are tubular shaped long and slender, longer than they are thick o It is split into 3 regions… § Epiphysis • proximal and distal region of the long bone. Hence the articulating ends of the long bone § Diaphysis • is the shaft of the long bone, thus the location of medullary cavity § Metaphysis • region between the Epiphysis and the Diaphysis • Corresponds to the location of the epiphyseal plate/line. o They contain the largest medullary cavity in the body o They are the major site of red bone marrow o They are highly vascularised o They are the sight of growth as they contain epiphyseal plates § Epiphyseal plates are a layer of hyaline cartilage within the bone and they appear at both end of the bone. § These plates elongate the bones and in early adulthood § the epiphyseal plate is replaced by bone and becomes the epiphyseal line.

Short Bones -

cuboidal shaped and usually small and boxy

Flat Bones -

thin and roughly parallel surfaces and usually provide protection.

Irregular bones

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are various complex shapes with short, flat, notched or rigid surfaces

Sesamoid Bones -

sesame seed shaped bones Are small and flat because they develop within a tendon usually near a joint They protect tendons from excessive wear and change the angle of the tendon.

Bony Landmarks Every projection, depression and opening found on the surface of all bones is a bony landmark. Provides fixed point that determines the positions of joints (articular surfaces) and surrounding soft tissues (tendons, muscles, blood vessels, nerves) Bony landmarks appear: • • • •

At articular surfaces Wherever tendons, ligaments or fascia attach to bone Where arteries lie adjacent to or enter bones In relation to the passage of a tendon (often to direct the tendon) to control movement at a joint.

Articular surfaces of Bone •

Head

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Neck

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large, round articular end of long bones

o relatively narrow portion proximal to the head Condyle o rounded, knuckle like prominence at the end of the bone, often occurring in pairs which are articular regions Epicondyle o eminence superior or adjacent to condyle

Attachments of Bone • •

Trochanter o large blunt elevation usually has a greater and lesser. Line/Ridge o thin linear elevation, often with a rough surface

Note: Foramen is the passage through a bone

Joint Types Joints can be divided and categorised by either function or structure. By function Synarthrosis • • • •

No movement the bony edges are quite close together and may even interlock Extremely strong joints are located where movement between the bones must be prevented. e.g cranial joints

Amphiarthrosis • • • •

little movement they permit more movement than synarthroses but are much stronger than a free movable joint articulated bones are connected by collagen fibres or cartilage e.g pubic symphysis

Diarthrosis • • •

free movement a form of joint articulation or synovial joint that permits free movement e.g the shoulder

By structure Fibrous joints •

joints where the articular surface of the bones are attached to each-other through fibrous connective tissue.

Cartilaginous joints •

are joints firmly held together by a thin layer of hyaline cartilage and/ or fibrocartilage.

Synovial Joints • •

a freely movable joint covered with a layer of articular cartilage within a joint cavity that contains synovial fluid. The fluid lines with synovial membrane and reinforced by a fibrous capsule and ligaments.

Accessory structures of synovial joints include... Fat Pads -

are localised masses of adipose tissue covered in a layer of synovial membrane. They protect the articular cartilage and act as packing material for the joint

Tendons -

collagen bands that connect a skeletal muscle to an element of the skeleton. Tendons passing across or around a joint may limit the joints range of motion and provide mechanical support for it

Bursae -

small pockets filled with synovial fluid that cushion adjacent structures and reduce friction

Menisci -

disc like structures of fibrocartilage within a joint to aid in shock absorption

Movements of Synovial joints § §

Synovial joints have gliding movements, angular movements can perform circumduction and rotation

Types of Synovial joints Gliding joints •

articular surfaces that are flat and allow glide.

Condylar joints • •

oval articular surface within a depression. They allow angular motion

Hinge joints •

joint surfaces are arranged to allow only back and forth movement in a single plane.

Vertebrate Animal Diversity Body Plans are a particular set of morphological and developmental traits integrated into a functional whole. this allows comparison between organisms. The organisation of tissues is a body plan and how they have specialised cell groups and are separated by membranous layers describes their organisation. Another body plan involved is early embryology its similar across vertebrates

Binomial Nomenclature "genus species" How the classification goes is by this levelling in ascending order of more inclusive is species, genus, family, order, class, phylum, kingdom, Domain One taxonomic unit is called a taxon animal phylogeny involves evolutionary relationships that have shared characteristics due to common history or evolutionary history. Animal phylogeny can form phylogenetic trees which can track morphological, developmental and molecular similarities.

Chordates Vertebrates belong to the Deuterostomes (a major linear of the animals) -

a recently recognised phyla and they are defined by molecular characteristics and embryonic developments and this group include 2 phyla: o echinoderms o chordates or vertebrates (these are sister phyla)

Four exclusive chordate characteristics are... •

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the notochord o a stiff but flexible rod that run anterior to posterior and provides some type of structural skeletal stability and support Dorsal hollow nerve chord o effectively the nervous system of the animal that also runs anterior to posterior Pharyngeal slits o for feeding, breathing o turn into other structures in later stages of development o first thought to have functioned as suspension feeding devices Post anal tail

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used for locomotion and is muscular

Chordates are broken in 3 subphyla 1. Cephalochordates or Lancelets o Small, only a few cm long o Around 20 species o suspension feeders o retain basic characteristics of chordate body plan at mature dev 2. Urochordates or Tunicates o sea squirts generally o highly modified o sessile chordates o the 4-chordate characteristic are only seen in development 3. Vertebrates o chordates with a backbone o form an endoskeleton § is light can support body weight and can grow in the body § not seen in any other phylum seen in the animal kingdom

Early Vertebrates Jawless Vertebrates Only 2 types of vertebrates are jawless: Hagfish and Lampreys -

these are 2 sister groups that represent the oldest extant vertebrate lineage only jawless vertebrates only 38 species in each group they are/have… o slow moving o no paired appendages o rudimentary vertebrae

Recognised as chordates based on molecular characteristics as vertebrae are hard to identify Jawed Vertebrates/Gnathostomes This is most vertebrates. Have jaws and mineralised skeletons as this was clearly a major evolutionary advantage -

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many fossil groups o 440-420 mya there was a lot of evolutionary change that caused large diversification of this group most extant vertebrates belong to this group

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gave rise to 3 groups o Chondrichthyes § Cartilaginous fishes § Skeletons are predom. Cartilage § Their loss ossified bone is a derived condition and more primitive sharks tend to have more ossified bone § Sharks, stingray, chimeras and ratfishes o Actinopterygii, Actinistia, dipnoi § Dotn share a recent common ancestor its older § Actinopterygii • Rayfins • Fins support dermal rays • Muscles don’t extend into fins • Dominant class of vertebrates (27,000) • Habitats include marine and freshwater § Lobe Fin fish • Rod shaped bones • Muscles • Very few extant species o Coelacanths and lungfish • Locomotion o Swimming o “walk” under water their jaws developed from pharyngeal slits o like in cephalochordates these are used for filter feeding o as evolution progressed, animals moved away from this o the skeletal rods that were present associated with gill slits modified over time to become part of the cranium § formed the jaw simultaneously we see the dev of paired appendages o contribute to their success and dominance in every habitat

Evolutionary Transition to Land Tetrapods are lobe fins with limbs -

this gave rise to amniotes

A lot is known about the evolution of tetrapods due to the extensive fossil record Tiktaalik -

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represents an evolutionary transition like a fish… o had gills o had full set of scale unlike a fish …

o had a full set of ribs and lungs to help it breath air and support its body weight o had a neck and shoulders to allow it to move its head, common in land animals o bones of front forelimbs show a pattern found in all limbed animals § strong humerus connected to scapula followed by radius and ulna and then smaller wrist bones § rear limbs are more robust and stronger than a fish § stronger pelvis

Evolution of limbs with digits These animals needed to have… -

developed necks o to support the head stronger vertebral columns o greater force of gravity Ribs o reduced so body movement side to side supporting girdles

Amphibia These animals have all these features^^^. -

external fertilisation o eggs in water larvae are aquatic o have gills and finned tails adults (like tetrapods) o legs o lungs o often terrestrial o moist habitats

Amniotes These are considered some of the most successful as they dominate land. They have 2 defining characteristics: The Amniotic egg and thicker(keratinised) skin Amniotic egg -

the amniotic egg of most reptiles and some mammals has a shell o to slow the dehydration of the egg in air o allows it to occupy a much larger array of habitats

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o most mammals have lost this feature has 4 import...