skeletal system 2023 Flashcards
three types of skeletons
-hydrostatic
-endoskeleton
-exoskeleton
describe the hydrostatic skeleton
-consists of a fluid-filled cavity surrounded by muscles
-fluid provides support against which muscles contract
-hydrostatic skeletons occurs in INVERTEBRATE animals with soft bodies
eg- jellyfish, earthworms, flat worms and round worms
advantages and disadvantages of hydrostatic skeleton
animals with a hydrostatic skeleton don’t require a specialised support system
-can’t perform fast movements
-hydrostatic skeletons occur in animals that lives in a moist environment
-limits the size of an animal
-hardly provides protection to the animal
describe the exoskeleton
-external skeleton that occurs on the outside of the animals body
-found in invertebrate animals (largest group is the arthropods)
-an exoskeleton consists of a polysaccharide, chitin (sometimes hardened with calcium carbonate)
advantage and disadvantages of the exoskeleton
-supports and protects underlying tissue and organs from injury
-makes movement possible
-prevents the body of the animal from desiccation (drying out)
-limits the size of the animal (larger the animal, larger the exoskeleton)
-limits growth
-impermeable to gazes and special respiratory organs with openings to the outside are required
describe the endoskeleton
-internal skeleton that occurs inside the animals body
-consists mainly of bone and cartilage that are found in VERTEBRATE animals
what is the advantages and disadvantages of the endoskeleton
-provides structural support and gives body shape
-more vulnerable to desiccation, heat and cold than animals with an exoskeleton
inveterate animals
doesn’t have a vertebral column (no internal skeleton)
-ab 95% animal species
-invertebrate animals have either hydrostatic skeleton or an exoskeleton
what are the six functions of the human skeleton
movement- plays a role in movement together with the muscles and joints
protection- protects sensitive organs such as the brain, heart and lungs
support- gives body strength and shape
mineral storage- calcium and phosphates are stored in bone
hearing- three ear ossicles in each ear transmits sound waves to internal ear which makes hearing possible
blood cell formation- white and red bloods are formed in the red bone marrow
describe the structure of the human skeleton
206 bones and is divided into two sections
-axial skeleton
-appendicular skeleton
describe the axial skeleton and what it consists of
-forms the central axis that keeps the body upright
-all the other parts of the endoskeleton are attached to it
-it protects the brain, sense organs, spinal cord, heart and lungs
the axial skeleton consists of
-skull
-vertebral column
-rib cage
what two groups of bones does the skull consist of
bones of the cranium
facial bones
describe the cranium and it’s function
-cranium consists of EIGHT flat bones that are immovably joined to each other with serrated sutures
-cranium encloses the brain and protects it
what does the facial part of the skull consist of
consists of fifteen irregular bones that form the forehead, cheeks, nose, temples and upper and lower jaws
how many teeth do adult humans have and it’s arrangement
32 permanent teeth
-the human dental formula 2.1.2.3
-———
2.1.2.3
2 incisors
1 canine
2 premolars
3 molars
-16 in each upper and lower jaw
describe the vertebral column
-consists of 33 bones, the vertebrae, which joined together by ligaments
what are the five different types of vertebrae’s and it’s amounts
seven cervical vertebrae
twelve thoracic vertebrae
five lumbar vertebrae
five sacral vertebrae
four vertebrae that form the coccyx
the first 24 vertebrae is known as
true vertebrae
the last nine vertebrae is known as
false vertebrae
what gives the the vertebral column an s shape
cervical
thoracic
lumbar
sacral
-this makes the colour flexible
what is the function of the vertebral column
supports the skull
protects spinal cord
place of attachment for ribs, the pectoral and pelvic girdle
what’s the rib cage
12 thoracic vertebrae
12 pairs of ribs and sternum
what’s the sternum
long, flat dagger shaped bone at the front of the rib cage
where are the 12 pairs of ribs attached
attached to the back of vertebral column
what are the first seven ribs
attached directly to the sternum and is known as true ribs
what are the next three pairs of ribs
attached to the preceding rib and is known as false ribs
what about the last two pairs of ribs
they are not attached to the sternum and are called floating ribs
what is the function of the rib cage
protects organs (heart and lungs)
what does the appendicular skeleton consist of
pectoral girdle
pelvic girdle
upper lumps
lower limbs
what is the pectoral girdle
consists of two scapulae at the back and two clavicles in the front
what kind of socket does the scapula have
a shallow socket known as the glenoid cavity into which they head of the humerus fits to form a ball and socket joint
how many bones are the upper limbs made of
6 limbs
what’s the humerus
a long bone that stretches from the pectoral girdle where it forms a ball and socket joint with the scapula
what’s the ulna
largest bone in the forearm is situated on the PINKY finger side
-c shaped and articulates with the humerus to form an elbow
what is the radius
the radius is the thinner of the two bones in the forearm and is situated on the THUMB side
-articulates with the carpals form the wrist joint
what are the carpals
8 small, short bones that are arranged in two rows of four
what are metacarpals
five small bones that form the palm of the hand
what are phalanges
forms the fingers and consist of 14 bones, three in each finger expect the thumb
what is the pelvic girdle
consists of two hip bones that are joined in the middle by a semi movable joint (pubic symphysis)
what are the hip bones made of
ilium
ischium
pubis
what are the hip bones attached to
the sacrum
how many types of bones is the lower limbs made of
7 different types of bones
what is the femur
longest and largest bone in the body
-the upper end of the femur articulates with the hip bone forming a ball and socket joint
-on the lower end there are two articular condyles that articulate with the tibia to form a HINGE joint of the knee
what’s the patella
the kneecap
-a triangular bone that occurs in front of the femur and forms part of the knee joint
what is the filbila
largest bone of the two bones in the lower log
what are tarsals
seven bones that form the ankle of which the largest bone (calcaneum) the heel bone occurs at the back
what muscle is attached to the heel bone
the calf muscle
what are the metatarsals
five bones that form the arch of the foot
what are the phalanges
toe bones. 14 bones, 3 in each toe expect the big toe
what is a joint
a junction in the skeleton where two or more bones meet and are joined by ligaments or cartilage
how is a joint classified
by its degree of movement and it’s categorised into three classes
immovable
semi movable
freely movable
what an immovable joint
a joint that doesn’t allow movement
what’s a semi movable joint
allows a slight degree of movement
what’s a synovial joint
allows free movement
what are the three types of synovial joins
ball and socket - head of one fits into the socket of another
pivot - one bone rotates around another
gliding - flat articular surface, one bone slides over another
how do antagonistic muscles work
one contracts, the other relaxes
what are rickets
deficiency disease where bones become soft
-lack of vitamin D
what is osteoporosis
disease of the bone density
-lack of calcium
what is arthritis
disease that causes severe pain and a loss of movement in joints
what is osteoarthritis
bones in a joint grinding against each other causes inflammation
what is rheumatoid arthritis
synovial membranes in joints thicken and produce too much synovial fluid which causes inflammation
