Anatomy Flashcards
What is the cardiovascular system comprised of?
Arterial System
Heart
Venous System
What are the 4 cardiac valves and where are they located?
- Tricuspid valve = RA + RV
- Pulmonary valve = RV + Pulmonary Trunk
- Mitral valve = LA + LV
- Aortic Valve = LV + Aorta
Describe the journey of blood through the heart
Blood flows in through the Superior or Inferior Vena Cava into the right atrium of the heart, through the tricuspid valve into the right ventricle.
Blood flows through the Pulmonary valve into the pulmonary trunk into the lungs and back through the pulmonary artery.
It passes into the left atrium through the mitral valve into the left ventricle through the aortic valve into the aorta.
What are the 3 layers of the heart (From external to internal)
- Epicardium (external)
- Myocardium
- Endocardium (Internal)
What happens in systole?
Contraction
What happens in diastole?
Relaxation
What chamber forms the right border of the heart?
Right atrium
What chamber forms the anterior border of the heart?
Right Ventricle
What chamber forms the posterior border of the heart?
Left Atrium
What chamber forms the left border of the heart?
Left Ventricle
What are the 3 layers of blood vessels (internal to external)?
- Tunica Intima
- Tunica Media
- Tunica Adventitia
Describe the conduction system of the heart.
- Electrical impulse starts at the SA node (Both atria contract)
- Travels to AV node at atrioventricular septum
- Travels down right and left bundles in interventricular septum
- Spreads out to myocardium through conducting fibres (both ventricles contract)
Describe features of arteries
- High pressure
- Pulsatile
- Carry oxygenated blood
What is an end artery?
only arterial blood supply to a given area of the body. Occlusion of an end artery results in infarction.
What is infarction?
irreversible cell death due to hypoxia.
Describe sympathetic Tone?
Sympathetic Tone is the background low level of contraction of smooth muscle in arterioles. This is due to tonic conduction of action potentials to arterioles by sympathetic nerves.
What is vasodilation?
Vasodilation is relaxation of the smooth muscle and widening of the lumen to increase blood flow.
What is vasoconstriction?
Vasoconstriction is the contraction of smooth muscle to reduce blood flow to the organ/tissue.
What is an anastomosis?
Anastomosis is where arteries connect with each other without intervening capillary network. This provides alternative routes for blood to flow to supply the cells distal to an arterial occlusion.
What is an example of an anastomosis?
The Circle of Willis in the brain
What are collateral arteries?
Alternative routes in an anastomosis.
What is a disadvantage of collateral arteries?
One disadvantage is that collaterals bleed from both sides of the cut.
What are the branches of the aorta?
- Brachiocephalic trunk
- Left common carotid artery
- Left subclavian artery
Describe features of veins
- Low pressure
- Deoxygenated blood
- Non-pulsatile
How is venous blood pumped back towards the heart?
- Venous valves
- Skeletal muscle pump
- Venae Comitantes - Arterial pulsations pushes venous blood along towards the heart.
What are the 2 main venous systems?
Hepatic Portal Venous System
Systemic Venous System
What is the function of the hepatic portal venous system?
drains blood from absorptive parts of the GI tract and associated organs to the liver for cleaning.
What is the function of the systemic venous system?
drains venous blood from all other organs + tissues into the superior or inferior vena cava.
What do lymphatic capillaries collect?
Tissue Fluid
What is the tissue fluid called once it has entered the lymphatic capillaries?
Lymph
What happens to lymph once its in the lymphatic capillaries?
Lymphatics can carry lymph through lymph nodes.
Where do superficial lymphatics drain into?
deep lymphatic vessels.
What is the only lymph vessel large enough to see on dissection?
Thoracic Duct
When can lymph nodes be palpated?
When fighting an infection or cancer
What does the axial skeleton include?
bones of the skull, neck and trunk
What does the appendicular skeleton include?
bones of the pectoral girdle, upper limbs, pelvic girdle and lower limbs.
What are the 3 types of bony features?
- Functional - best shape for the job
- An adjacent structure applying force - moulding it’s shape.
- An adjacent structure developing at the same time - grows around the structure
Describe bone.
hard connective tissue, functions include: - support and protection, - calcium metabolism, - red blood cell formation etc.
Describe cartilage
less rigid than bone.
Located where mobility is required.
Describe a synovial joint
the ends of bones are encased in smooth cartilage. E.g., Hinge - elbow, Saddle - carpometacarpal, ball and socket - hip
Describe a primary cartilaginous joint
bones are connected by hyaline cartilage e.g., growth plates
Describe a secondary cartilaginous joint
a flat disk of fibrocartilage connect bones e.g., pubic symphysis
Describe a fibrous joint
adjacent bones are strongly united by fibrous connective tissue e.g., sutures on the skull.
Function of tendons?
attach the muscle to bone.
What is an aponeurosis?
a flattened tendon and attaches to soft tissue rather than bone.
Describe the flexion withdrawal reflex
- touch something dangerous
- sudden withdrawal
- nerve connections are at spinal cord level not brain.
Describe the stretch reflex?
- tendon hammer used to apply a brief, sudden stretch to the muscle via the tendon
- reflex is twitch of the muscle belly
Describe the reflex arc?
- sensory nerve from muscle detects stretch and tells the spinal cord.
- Synapse in the spinal cord between sensory and motor nerves
- Motor nerves from spinal cord message to muscle to contract
What does a normal stretch reflex indicate?
indicates that the following are functional:
- the muscle
- sensory nerve fibres
- motor nerve fibres
- spinal cord connections
- neuromuscular junction
- descending controls from the brain
Describe paralysis?
a muscle without a functioning motor nerve supply is “paralysed”. It cannot contract. It has reduced tone
Describe spasticity
the muscle has an intact and functioning motor nerve. The descending controls from the brain are not working. There is increased tone.
Describe atrophy
wasting of the muscles. Myocytes become smaller reducing the muscle’s bulk. Develops as a result of inactivity
Describe hypertrophy
opposite of atrophy. Skeletal muscle enlarges. Each individual myocyte enlarge.
Female gamete
oocyte or ovum produced in ovaries
Male gamete
spermatozoa produced in testes
Name for diploid fertilised cell
zygote
In Normal fertilisation…
- ovum from ovary to ampulla of uterine tube
- Many spermatozoa from testis to vagina
Describe the pelvic cavity
lies within the bony pelvis. Continuous with abdominal cavity between the pelvic inlet and outlet.
Describe the pelvic floor
internal wall of skeletal muscle. Separates pelvic cavity and perineum. It’s openings include distal alimentary, reproductive and renal tracts.
Describe the perineum
inferior to pelvic floor between proximal parts of lower limbs
What forms the pelvic roof
Formed by the parietal peritoneum
Describe parietal peritoneum
The parietal peritoneum forms lining of abdominal cavity. Firmly attaches to walls and drapes over pelvic viscera.
Outline female surface anatomy
- external urethral orifice (urinary tract)
- vaginal orifice (genital tract)
- Anus (GI tract)
Outline male surface anatomy
- scrotum - contains the testes
- Urethra - passing urine and ejaculation of sperm
- Prepuce
- Anus
Reproductive organ in females
Ovaries
Accessory organs in females
uterine tubes, uterus and vagina
Layers of the uterus walls
- perimetrium
- myometrium
- endometrium
Where does fertilisation usually occur?
Ampulla
Where does implantation occur?
Body of the uterus
Describe menstruation and fertilisation
- Ova develop in the ovaries
- Each menstrual cycle, 1 ovum is released from surface of ovary into peritoneal cavity
- Ovum is gathered by fimbriae into infundibulum of uterine tube.
- Moved along uterine tube by cilia
- During menstruation, an unfertilised ovum is expelled by contractions of the myometrium.
Describe ectopic pregnancy
fertilised ovum implants out with the uterine cavity. Potential emergency - danger of haemorrhage
What is female sterilisation?
tubal ligation - both uterine tubes either clipped, cut or cauterised which blocks the lumen.
What is the reproductive organ in males?
Testes
What are the accessory reproductive organs in males?
vas deferens, seminal glands, prostate glands and penis
Describe testes development.
- Testes originate on the posterior wall of the abdominal cavity
- By birth they descend into the scrotum
- Through the anterior abdominal wall through inguinal canal
- Tube that sperm pass through follows the testis into the scrotum (vas deferens)
- The vas connects the testes to (almost) the urethra.
Describe production of sperm
- Temp 1 degree C below core temp
- Dartos muscle helps to control temperature
- 64 days to mature
- Sperm pass to the testes
- Then into the head of the epididymis
- Epididymis become vas deferens
What does the spermatic cord include:
- vas deferens
- Testicular artery
- Pampiniform plexus of veins
Describe testicular torsion
twisting of the spermatic cord which disrupts blood supply causing severe pain. Danger of testicular necrosis
Describe the journey of sperm
- Sperm develop in testes in scrotum
- Pass from testes via vas deferens which lie within spermatic cord.
- Each spermatic cord passes through the anterior abdominal wall within the inguinal canal to reach the pelvic cavity
- Within the pelvis each vas deferens connects with the duct from a seminal gland (produces seminal fluid) to form one ejaculatory duct containing semen.
- The right and left ejaculatory ducts join together within the prostate gland (immediately inferior to the bladder) and drain into the urethra.
- The urethra opens at the external urethral meatus of the penis.
Describe male sterilisation
vasectomy - vas deferens are transected and it’s lumen sutured closed.
What is involved in the central nervous system?
Brain
Spinal cord
Central controller
What is involved in the peripheral nervous system?
- all other nerves not within the CNS
- spinal nerves (connect with the spinal cord)
- cranial nerves (connect with the brain)
- autonomic nerves
- organs, smooth muscle, glands
- visceral afferents
- sympathetic nerves
- parasympathetic nerves
- wiring
What is a neuron?
basic unit of the nervous system
Describe ganglion
a collection of nerve bodies in the PNS
Describe Nucleus
a collection of nerve bodies in the CNS
Function of motor neuron (efferent)
action potentials towards the body wall, body cavity or organ
Function of sensory neuron (afferent)
action potentials towards the brain
Describe a nerve
bundles of axons (nerve fibres) wrapped in connective tissue traveling to/from the same region or structure.
What does soma include?
- head and neck walls
- chest walls
- back
- diaphragm
- abdominal wall
- pelvic wall
- limbs
What modalities can a nerve posses?
- Somatic sensory function e.g., pain from body wall
- Somatic motor function e.g., skeletal muscle contracts
- Special sensory function e.g., sight
- Visceral afferent function e.g., pain from organ
- Sympathetic Function e.g., cardiac muscle contracts/relaxes
- Parasympathetic Function e.g., cardiac muscle contracts/relaxes
What is the outermost layer of the cerebral hemispheres called?
Cortex
What create grooves in the brain surface?
Gyri and sulci
What is the name and modality of CN I?
Olfactory Nerve - Sensory
What is the name and modality of CN II?
Optic Nerve - Sensory
What is the name and modality of CN III?
Oculomotor - Motor
What is the name and modality of CN IV?
Trochlear - Motor
What is the name and modality of CN V?
Trigeminal - Both
What is the name and modality of CN VI?
Abducent - Motor
What is the name and modality of CN VII?
Facial - Both
What is the name and modality of CN VIII?
Vestibulocochlear - Sensory
What is the name and modality of CN IX?
Glossopharyngeal - Both
What is the name and modality of CN X?
Vagus - Both
What is the name and modality of CN XI?
Spinal Accessory Nerve - Motor
What is the name and modality of CN XII?
Hypoglossal Nerve - Motor
What are cranial fossae?
Foraminae for cranial nerves to enter and exit cranial cavity
What cranial nerve passes through cribriform plate of the ethmoid bone?
CN I
What cranial nerve passes through optic canal?
CN II
What cranial nerve passes through superior orbital fissure?
CN III, IV, Va, VI
What cranial nerve passes through foramen rotundum?
CN Vb
What cranial nerve passes through internal acoustic meatus?
CN VII and VIII
What cranial nerve passes through foramen ovale?
CN Vc
What cranial nerve passes through jugular foramen?
CN IX, X, XI
What cranial nerve passes through hypoglossal canal?
CN XII
What does the spinal cord pass through?
Foramen Magnum
How is the spinal cord protected?
By vertebral canal
What are the 4 segments of the spinal cord?
Cervical
Thoracic
Lumbar
Sacral/coccygeal
How many enlargements does the spinal cord have and what are they called?
2 - cervical and lumbosacral
How many spinal nerves are there?
31: 8 x C 12 x T 5 x L 5 x S 1 Co
What level does the spinal cord end at?
L1/L2 IV disc
What is the cauda equina?
where the lumbar and sacral spinal nerve roots have to descend in the vertebral cord to their respective intervertebral foraminae
How many vertebrae are there?
33: 7 x C 12 x T 5 x L 5 x S (fused to form 1 sacrum) 4 x Co (fused to from 1 coccyx)
How are spinal nerves named?
Based on the vertebrae directly above it (except for C8)
Describe posterior rami
Smaller and supply small posterior strip
Describe anterior rami
Larger and supply the remainder of the posterior part, the lateral and the anterior parts of the strips and supplies all the limbs
Describe the route of sensory axons
- Move from the spinal nerve
- Into the posterior root
- then into the posterior rootlets
- then into the posterior horn of the spinal cord
