Anatomy Flashcards
What are the two sides of the heart divided by and why is this needed?
The septum, without this there would be the mixing of blood which would reduce the efficiency of the heart.
How is heart location described?
- In the thoracic cavity.
- Deep to the sternum.
- Deep to costal cartilages.
- Protected by ribs, vertebrae and sternum.
- Between the lungs (mediastinum)
- More on the left side than the right.
Describe the three layers of the heart
1) Epicardium- this is external, visceral serous pericardium
2) Myocardium- middle, muscle layer
3) Endocardium- internal lining that is continuous with endothelium of blood vessels connecting with the heart.
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Name the 4 cardiac valves and describe location
Pulmonary valve (between right ventricle and pulmonary trunk) Tricuspid valve (between right atrium and right ventricle) Mitral/bicuspid valve (between left atrium and left ventricle) Aortic valve (between left ventricle and aorta)
What do valves prevent?
The backwards flow of blood
Describe the mediastinum and where the heart is
- The Mediastinum is the area that lies in between the lungs.
- It is divided into the inferior and superior mediastinum.
- The inferior mediastinum is further divided into anterior, middle and posterior.
- The heart is located in the middle mediastinum.
Describe the pericardium
• The Pericardium forms the boundaries of the middle mediastinum and is the tissue surrounding the heart.
• It has two layers:
1) The fibrous pericardium- a thick outer layer that prevents overfilling.
2) Serous Pericardium- an inner membranous layer that secretes serous fluid. It reflects back on itself, it stops friction. There is a visceral layer of the serous pericardium that covers the heart and a parietal layer that lines the fibrous pericardium
What functions does the fibrous skeleton of the heart provide?
- Keeps orifices of valves patent
- Forms the fibrous rings of the cardiac valves
- Forms an electrical insulator by separating conducting impulses of atria and ventricles allowing one normal route for electrical conduction in the heart
How does the heart’s conduction system work?
Electrical impulse starts spontaneously at SA node (pacemaker), travel through cardiac muscle of atria and cause them to contract. Travel down through the septum and spreads out to myocardium through conducting fibres causing the ventricles to contract
What is fibrillation?
The uncoordinated contraction of the cardiac muscle
What are external factors that can also affect heart rate and force of contraction?
Nerves that supply the heart e.g. sensory nerves and motor nerves- these include sympathetic nerves that speed the heart up and increase force of contraction. Circulating hormones such as adrenaline can also have an effect.
What does pulmonary circulation refer to?
The circulation of blood in which deoxygenated blood is pumped from the heart to the lungs and oxygenated blood is returned to back to the heart.
Describe the route blood takes through the heart
Deoxygenated blood is taken back to the heart by the vena cava and into the right atrium and the ventricle, the pulmonary artery then takes the deoxygenated blood to the lungs where it is oxygenated and returned to the heart by the pulmonary vein. It is then pumped through the left atrium and ventricle before being pumped around the body by the aorta.
What is systemic circulation?
This is what occurs between the heart and the entire body.
What are great vessels?
Vessels directly connected to a chamber of the heart.
Why are arterioles said to have sympathetic tone?
Only the sympathetic nervous system effects blood vessels, as only contraction is active, relaxation is simply the act of not contracting so does not involve the parasympathetic system.
What are the four parts of the aorta?
Arch of the aorta, ascending aorta, thoracic aorta, abdominal aorta.
What is the blood supply to the brain provided by?
The circle of Willis.
What is the blood brain barrier created by and what is the purpose?
Tight junctions between brain capillary endothelial cells and this prevents the diffusion of some substances from capillary into the brain.
What are end arteries?
The only arterial blood supply to a given area of the body. The hands have true end arteries and the heart has false end arteries.
What is infarction
irreversible cell death due to hypoxia (lack of oxygen) caused by loss of arterial blood supply.
What does the ascending aorta branch into and what does the arch of the aorta branch into?
Ascending: left and right coronary artery
Arch: the brachiocephalic trunk, left common carotid artery, and left subclavian artery.
What does the abdominal aorta bifurcate into?
Common iliac arteries.
Name 7 peripheral pulses that can be tested?
- Carotid Pulse (in the neck)
- Brachial Pulse (upper limb)
- Radial Pulse (upper limb)
- Femoral Pulse (lower limb)
- Popliteal Pulse (lower limb)
- Posterior Tibial Pulse (lower limb)
- Dorsalis Pedis Pulse (foot)
What are the two main venous systems?
The hepatic portal venous system (drains blood from absorptive parts of GI tracts) and the systemic venous system (drains blood from all other organs and tissues).
What is the circulatory system made up of?
The cardiovascular and the lymphatic system.
What type of bone marrow makes red blood cells?
Red bone marrow- As you grow up this marrow turns yellow but in cases of extreme blood loss there is the possibility for it to revert back and make red blood cells.
What is the the Periosteum
A fibrous connective tissue sleeve surrounding bone.
What are the two types of bone?
Compact (cortical) and spongy (trabecular) bone.
Explain endochondral ossification
This explains how long bones grow. An initial small, hyaline cartilage version grows and turns into bone (ossifies). When the growth plate of hyaline cartilage finally ossifies, bone growth ceases and we have attained our final height.
Explain the five main categories of bone shape
1) Flat Bones: these are protective.
2) Long Bones: these are tubular and are longer in one dimension than in the other.
3) Irregular Bones: these are weird shapes e.g. vertebrae.
4) Sesamoid Bones: these form within a tendon, function is to restrict the amount of friction in the tendon.
5) Short Bones: these are cuboidal.
Explain reduction and fixation of a fracture
For the fracture to heal properly the broken ends must be brought together approximating their normal position. This is called reduction of the fracture. Reduction can be done surgically if needed. Surgical fixation can also be carried out which involves using titanium plates & screws to hold the ends of the bone in correct alignment.
What happens during bone healing?
The surrounding fibroblasts (connective tissue cells) proliferate and secrete collagen which forms a collar of callus to hold the bones together.
Name the parts of the axial and Appendicular skeleton
Axial is skull, spine, ribs and sternum
Appendicular is pectoral girdle, upper limbs, pelvic girdle, lower limbs.
What is the cranial vault?
The space in the skull within the neurocranium, occupied by the brain.
What is a le fort fracture?
A fracture of the mid face, there are three grades depending on severity.
Describe the vertebral column
There are five regions and 33 vertebrae in total:
- 7 cervical (C1-C7) these are the vertebrae of the neck.
- 12 thoracic (T1-T12) these attach to ribs.
- 5 lumbar (L1-L5) vertebrae of the back.
- 5 sacral (fused to form 1 sacrum).
- 4 coccygeal (fused to form 1 coccyx).
What are the three types of muscle?
1) Cardiac- involuntary and striated, allows the heart to beat.
2) Smooth muscle- involuntary and non-striated.
3) Skeletal muscle- voluntary, this allows conscious movement, it is very striated.
What allows skeletal muscles to move a joint?
They must cross the joint.
What is an aponeurosis
A flattened tendon most commonly associated with flat muscles. They attach muscle to soft tissue rather than bone.
Describe two types of reflex
1) Flexion withdrawal reflex- This occurs when you touch something potentially damaging and have sudden flexion to withdraw from the danger.
2) Stretch/ deep tendon reflexes- These protect against overstretching, normal reflex response to being stretched is to contract so the reflex results in a brief twitch in the normal direction. Examples are biceps jerk, triceps jerk, knee jerk and ankle jerk.
What does a normal stretch reflex indicate are functioning normally?
- Sensory nerve fibres
- Motor nerve fibres
- Spinal cord connection
- Neuromuscular junction
- Muscle
- “Descending controls” from the brain
What are two reasons for stretch reflexes not working?
- Paralysis caused by an absent reflex.
- Spasticity caused by an overactive reflex.
Define atrophy
The wasting away of muscles, cell size decreases.
Define hypertrophy
The opposite of atrophy, each individual myocyte enlarges.
What is cell hyperplasia
The number of muscle cells increases, this has negative consequences.
Describe where skeletal muscles are found and there appearance.
Skeletal muscles are usually found deep to the deep fascia. They have a shiny silver/grey colour and a tough fibrous connective tissue covering.
What is the fascia?
A fascia is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches, stabilizes, encloses, and separates muscles and other internal organs.
Name the compartments of the upper and lower limbs.
The thigh has three compartments- anterior, posterior and medial.
The leg has three compartments- anterior, posterior and lateral.
The arm has two compartments- anterior and posterior.
The forearm has two compartments- anterior and posterior.
Explain compartment syndrome
Fascia creates enclosed space and increased pressure caused by swelling of tissue or increase in fluid (bleeding) results in compartment syndrome. This effects functions of muscles or nerves.
Describe four functions of bones
Support & protection of the body organs.
Calcium metabolism.
Red blood cell formation.
Attachment for skeletal muscles.
What is a joint?
An articulation between adjacent parts of the skeleton (bones and cartilages).
Describe the compromises between mobility and stability in joints
- Increased mobility = decrease stability.
* Decreased mobility = increased stability.
Describe fibrous joints and the two subtypes
- These generally have limited mobility.
- They are quite stable.
There are two subtypes:
- Syndesmoses unite bones with fibrous sheet made of fibrous membrane, these are partially moveable.
- Sutures are joints between bones of skull, these have no movement.
Describe cartilaginous joints and the two subtypes.
• These have fairly limited mobility and are relatively stable.
• There are two subtypes:
- Primary cartilaginous- The bones are joined by hyaline cartilage and these joints permit growth in length of bone and are usually temporary. Ossification and fusion of the hyaline cartilage will occur and will turn to bone.
- Secondary cartilaginous- These are strong and slightly moveable and united by fibrocartilage. These joints are present in intervertebral discs. The fibrocartilage unlike the hyaline cartilage does not ossify.
Describe how both types of cartilaginous joints can slip
An example of primary slip is a slipped femoral epiphysis which refers to a fracture through the growth plate which results in slippage of the overlying end of the femur. A secondary example would be a slipped disc or disc herniation of an intervertebral disc.
Describe Synovial Joints
Surrounded by a synovial capsule that secretes synovial fluid to lubricate and nourish the joint as well as acting as a shock absorber. The joints are supported by tendons and ligaments.
Explain the five different subtypes of synovial joints
Pivot- > 45o of “shaking the head” rotation
Plane- minimal movement in one plane. (e.g. acromioclavicular joint)
Hinge- reasonable range of movement in one plane. (e.g. knee and elbow joint)
Ball and Socket- good ranges of multi-axial movement. (e.g. shoulder)
Biaxial- reasonable range of movement in one plane and less in another. (e.g. fingers)
What are three common injuries to joints?
Disruption of Soft Tissues- no change in joint just injury to ligaments and/or slipped disc
Subluxation- reduced area of contact between articular surfaces.
Dislocation- complete loss of contact between articular surfaces.
What happens in a dislocation of the temporomandibular joint?
The head of the condylar process of the mandible becomes “stuck” anterior to the articular tubercle of the temporal bone. The result is the patient’s mouth is wide open and cannot be closed. Dislocation can be unilateral (one TMJ only) or bilateral (both TMJs). The chin remaining in the midline suggests a bilateral dislocation
Describe the nerve supply of joints
Joints have an excellent nerve supply (explaining why dislocations are so painful).
What are synovial joints associated with?
They are associated with bursae (small fluid filled sacs) that help prevent friction around the joint.
What are the three layers of the body of the uterus?
Perimetrium
Myometrium
Endometrium
Describe the path of ovum in the menstrual cycle
- Each menstrual cycle, 1 ovum is released from surface of ovary into peritoneal cavity
- Ovum is gathered by fimbriae into infundibulum of uterine tube and moved along the uterine tube by cilia
- During menstruation, an unfertilised ovum is expelled by contractions of the myometrium which is what causes cramping/ pain.
What happens in an ectopic pregnancy?
A fertilised ovum implants out with the uterine cavity. 97% of the time it is a tubal pregnancy and very rarely there is an abdominal pregnancy.
Describe female sterilisation
It is called tubal ligation and involves both uterine tubes being, clipped, cut or cauterised.
What helps keep the seminiferous tubules one degree below core body temperature?
The Dartos muscle helps to control this temperature, contracting causes skin to thicken and lose less heat.
Describe male sterilisation
Involves a vasectomy which is when the vas deferens is transected and its lumen sutured closed.
What are the branches of the thoracic aorta?
Intercostal, Bronchial, Mediastinal, Phrenic Arteries and Oesophageal
Describe the order of the GI tract pathway
- Oral Cavity
- Pharynx
- Oesophagus
- Stomach
- Small Intestine
- Large Intestine
- Rectum
- Anus
What is the function of the oral cavity?
Sensing, salivation, chewing, initiating swallowing.
Describe the parts and function of the pharynx
Defence against infection (tonsils), swallowing, airway protection. There are three parts to the pharynx, nasopharynx, oropharynx and laryngopharynx. The oro and laryngo are also used in the respiratory pathway too so there is the risk of material going down the wrong pathway.
Describe the function of the oesophagus
Transit from pharynx to stomach, movement by peristalsis.
Describe the function and structure of the stomach and small intestine
Transit, defence against infection, digestion and absorption. The stomach is a small J shaped organ that acts as a blender. The small intestine has three parts, duodenum, jejunum and ileum.
Describe the structure and function of the large intestine and anus
Transit, reabsorption of water and electrolytes, stool formation and waste excretion. Large intestine is located in all four quadrants with parts named: caecum, ascending colon, transverse colon, descending colon and sigmoid colon. Muscular wall of the rectum and anal canal is smooth muscle. The sphincter forming the anus is skeletal.
Explain colicky pain
- As peristalsis comes in waves, a patient with a GI tract obstruction tends to experience pain that “comes and goes”
- This is called “colicky pain”
Describe the peritoneum
- A continuous serous membrane, which secretes lubricating peritoneal fluid into the peritoneal cavity
- Lines abdominal cavity and invests viscera
- It has two continuous layers; visceral and parietal
- Visceral peritoneum invests an organ
- Parietal peritoneum touches the internal body wall
Describe anatomical sphincters
- Anatomical sphincters are discrete areas where muscle completely encircles the lumen of the tract
- Anatomical sphincters can be composed of smooth muscle (e.g. pyloric sphincter) or skeletal muscle (e.g. external anal sphincter)
Describe the fore gut, mid gut and hind gut.
Foregut (Red) • Oesophagus to mid-duodenum • Liver + gall bladder • Spleen • ½ of pancreas
Midgut (Green)
• Mid-duodenum to proximal 2/3rds of Transverse colon
• ½ of pancreas
Hindgut (Purple)
• Distal 1/3rd of Transverse colon to Proximal ½ of Anal canal
Why are sensory neurons termed afferent?
They bring signals towards the CNS
Why are motor neurons termed efferent?
They project signals away from the CNS
What is the function of interneurons?
They are part of the CNS, they organise, relay and create circuits
What do the terms sulcus and gyrus refer to?
Sulcus refers to the groove. Gyrus refers to the bump created by the grooves.
Describe the brainstem
Starts with midbrain then pons (bit that sticks out) then the medulla oblongata. The brainstem becomes the spinal cord once it leaves the cranial vault via the foramen magnum.
Describe the conus medullaris and the cauda equina
The spinal cord is shorter than the vertebral column, the conus medullaris is the tapered lower end of the spinal cord. The cauda equina is the area below where the spinal cord ends and is a collection of nerves.
Describe grey and white matter in the brain and spinal cord
- Grey matter is on the outside of the brain and is full of cell bodies due to the large surface area.
- White matter is the inner area of the brain and contains many axons which are myelinated giving it the white appearance.
- In the spinal cord this flips round, white matter is on the outside and grey matter is on the inside.
Describe the 12 cranial nerves
- CN I Olfactory nerve*
- CN II Optic nerve*
- CN III Oculomotor nerve
- CN IV Trochlear nerve
- CN V Trigeminal nerve
- CN VI Abducent nerve
- CN VII Facial nerve
- CN VIII Vestibulocochlear nerve*
- CN IX Glossopharyngeal nerve
- CN X Vagus nerve
- CN XI Spinal accessory nerve
- CN XII Hypoglossal nerve
S S M M B M B S B B M M
How are the spinal nerves named?
They are named according to the vertebrae above it apart from C8 which exits between C7 and T1 vertebrae. There are five sacral spine nerves but only one coccygeal nerve co1.
What are nerve plexuses?
Area of intersecting nerves (anterior rami)
What are dermatomes?
Area (strip) of skin supplied by both the anterior and posterior rami of a spinal nerve
Describe the difference between somatic and autonomic nervous system
Somatic Nervous System
• Body wall
• External environment
• Can be controlled by conscious thought
Autonomic Nervous System
• Visceral motor system
• Internal environment
• Not controlled by conscious thought
Give examples of somatic sensations
SENSED BY MECHANORECEPTORS • Coarse touch • Fine touch • Vibration • Proprioception (feeling of where your body is in space)
SENSED BY THERMORECEPTORS
• Temperature
SENSED BY NOCICEPTORS (pain is well localised)
• Sharp
• Stabbing
Describe the somatic sensory pathway
- The somatic pathway for touch is a 3 neurone chain.
- In the left parietal lobe is the left primary somatosensory area, sensory AP’s arrive here from right side of body wall and vice versa.
- In this area sensations are brought into consciousness
Describe the somatic motor pathway
- The motor pathway has a two neuron chain
- Upper motor neurone originates from the opposite side from movement.
- The axons then cross over at brainstem and the lower motor neurone originates from the same side as movement and connects to the skeletal muscle.
What would a muscle without a functioning lower neuron look like?
It would be paralysed, unable to contract and therefore have reduced tone.
What would the muscle look like if the descending controls from the brain were not working?
It would be spastic (overactive reflex) and therefore have increased tone
What is the autonomic nervous system made up of?
The sympathetic (fight or flight) and parasympathetic systems (rest and digest)
What type of outflow does the sympathetic nervous system have?
Thoracolumbar outflow
Sympathetic system has a two neuron chain
What type of outflow does the parasympathetic system have?
Has a craniosacral outflow. This means all parasympathetic axons leave the CNS via cranial nerves III, VII, IX & X and via sacral spinal nerves.
Knee and hip have about how many degrees of flexion?
135
Shoulder has about how many degrees of flexion?
180
Sperm are produced in _____1_____, the sperm then pass to ____2____, then into ____3____, the __4___ then becomes _____5______
1 seminiferous tubules 2 rete testis 3 head of epididymis 4 epididymis 5 vas deferens
Main function of the lymphatic system?
Collect/ drain excess fluid and leaked plasma proteins.
