Anatomy of Spiny Dogfish Sharks

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Questions and Answers

Which of the following is NOT a component of the mandibular arch?

Palatoquadrate cartilages

Basapophysis (correct)

Adductor mandibulae process

Meckel's cartilages

What is the main function of the labial cartilage?

To attach jaw-closing musculature

To support the labial fold (correct)

To articulate with the ribs

To form the upper jaw

Which structure is considered the axial support within the centrum of a vertebra?

Radial Pterygiophores

Arcualia

Basapophysis

Notochord (correct)

What is the function of the basapophysis?

To serve as an attachment point for ribs (C) Signup and view all the answers

What is the main distinction between ceratotrichia and other skeletal elements?

Ceratotrichia are fibrous dermal rays (C) Signup and view all the answers

What is the primary supporting structure of the caudal fin proximally?

Hemal arches (D) Signup and view all the answers

Which of the following best describes the skeletal composition of the spiny dogfish shark?

Composed of cartilage with perichondral and endochondral ossification. (A) Signup and view all the answers

Which arch is modified to support the jaws?

Hyoid arch (B) Signup and view all the answers

What is the function of the adductor mandibulae process?

To serve as an attachment point for jaw-closing musculature (D) Signup and view all the answers

Which of the following structures is part of the spiny dogfish shark's external anatomy?

Ampullae of Lorenzini (A) Signup and view all the answers

What is the function of the teeth in spiny dogfish sharks?

To tear and grip prey, with replacement rows. (B) Signup and view all the answers

Which structure is part of the muscular system of the spiny dogfish shark, specifically along cutting line 1?

Myoseptum (B) Signup and view all the answers

What is the primary function of the claspers in male spiny dogfish sharks?

Assist in reproduction (B) Signup and view all the answers

Which structures compose the skeletal elements of the spiny dogfish?

Chondrocranium, splanchnocranium, vertebral column, and pectoral girdle. (C) Signup and view all the answers

What is present in both male and female spiny dogfish?

Abdominal pore (A) Signup and view all the answers

What is unique about the teeth of the spiny dogfish shark relative to most other fish?

They are constantly replaced by rows of new teeth. (C) Signup and view all the answers

What is the primary function of the spiracles in dogfish?

To draw water over the gills for respiration. (B) Signup and view all the answers

What skeletal feature of the dogfish contributes most to reducing their specific density?

The large, oil-filled liver. (A) Signup and view all the answers

Which of the following best describes the arrangement of the pectoral and pelvic girdles within the dogfish skeleton?

The pectoral and pelvic girdles are isolated components with no direct attachment to the rest of the skeleton. (D) Signup and view all the answers

Which structure of the chondrocranium in the dogfish supports the rostrum ventrally?

Rostral carina (B) Signup and view all the answers

What are the otic capsules within the dogfish's chondrocranium responsible for?

Housing the inner ears. (D) Signup and view all the answers

Which foramen in the dogfish chondrocranium serves as the large median opening for the spinal cord?

Foramen magnum (C) Signup and view all the answers

The splanchnocranium of the dogfish is primarily associated with which type of body structures?

The viscera of the head and associated arches. (D) Signup and view all the answers

How many visceral arches are present in the dogfish?

7 (B) Signup and view all the answers

Which structure articulates with the fin at the mesopterygium?

Glenoid surface (C) Signup and view all the answers

In the pectoral fin, which of the following represents the correct order of structures from proximal to distal?

Basal pterygiophores > radial pterygiophore > ceratotrichia (C) Signup and view all the answers

What is the primary function of the clasper in male sharks?

To bring sperm into the cloaca of the female. (C) Signup and view all the answers

Which of these is NOT a component of placoid scales?

Epidermis (A) Signup and view all the answers

What is the function of melanophores within the integument of sharks?

To control pigmentation of the skin and secretory cells. (C) Signup and view all the answers

Which term refers to the external openings of sharks located ventrolaterally on their snout?

Nares (D) Signup and view all the answers

What type of cartilage supports the labial pockets in sharks?

Labial (C) Signup and view all the answers

Which of the following is NOT an extrinsic eye muscle group?

Dorsal muscles (A) Signup and view all the answers

What is the primary function of the spiracular valve in sharks?

To close the spiracle opening (B) Signup and view all the answers

Where are the external pharyngeal slits located?

Posterior to each eye (D) Signup and view all the answers

What structure is found on the posterior surface of the spiracular valve?

Pseudobranch (C) Signup and view all the answers

What is the function of the interbranchial septa?

To separate the external pharyngeal slits (A) Signup and view all the answers

What is the main function of the lateral line system in sharks?

To detect pressure changes and vibrations in the water (A) Signup and view all the answers

Where do the endolymphatic ducts open to the surface?

Through the endolymphatic pores (B) Signup and view all the answers

What is the function of the ampullae of Lorenzini?

To function in electroreception (B) Signup and view all the answers

Which of the following is NOT true about the gill lamellae?

They are found on the posterior wall of the last slit. (C) Signup and view all the answers

What is the primary function of the lateral undulations of the tail and caudal fin in sharks?

To generate the propulsive force for forward movement. (A) Signup and view all the answers

Which of the following is a key characteristic of the clasper in male sharks?

It is an elongated, cylindrical, and grooved structure used for copulation. (D) Signup and view all the answers

What is the function of the abdominal pores in sharks?

They are thought to allow the removal of excess fluid from the pleuroperitoneal cavity. (D) Signup and view all the answers

Which anatomical structure in male sharks serves as the opening for both the genital and urinary ducts?

Urogenital papilla (B) Signup and view all the answers

What is the function of the ampullae located around the head of a shark?

They are used to detect electrical fields produced by other organisms. (C) Signup and view all the answers

Besides the lateral undulations of the tail and caudal fin, what other kind of fin is involved in the propulsive force of a shark?

No other fins are involved in propulsion. (C) Signup and view all the answers

What is the primary anatomical structure that serves as a common exit point for the urinary, reproductive, and digestive tracts in sharks?

Cloaca (D) Signup and view all the answers

What is a key difference between the urogenital papilla in male sharks and the urinary papilla in female sharks?

Only the urinary ducts open at the tip of the urinary papilla in females. (B) Signup and view all the answers

What internal feature of the valvular intestine significantly enhances its absorptive capacity?

A spiral valve (D) Signup and view all the answers

Which chamber of the spiny dogfish shark's heart receives venous blood from the body?

Sinus venosus (B) Signup and view all the answers

What is the primary role of the rectal gland in spiny dogfish sharks?

Excreting salt (D) Signup and view all the answers

In the spiny dogfish shark, the liver is characterized by which of the following?

Three distinct lobes and contains buoyant oils (B) Signup and view all the answers

What is the function of the siphon in male spiny dogfish sharks?

Expelling fluid that contributes to seminal fluid (C) Signup and view all the answers

How are the kidneys positioned relative to the parietal peritoneum in the spiny dogfish shark?

Retroperitoneal (C) Signup and view all the answers

What is the primary function of the myosepta in the muscular system of the spiny dogfish?

To separate and support the myomeres (A) Signup and view all the answers

What is the function of the conus arteriosus in the circulatory system of a spiny dogfish?

It allows blood to leave the heart (D) Signup and view all the answers

Which muscular structure in the spiny dogfish is responsible for closing the mouth?

Adductor mandibulae muscle (B) Signup and view all the answers

Where are the oviducts located in female spiny dogfish sharks?

On the ventral surface of each kidney (A) Signup and view all the answers

What is the function of the horizontal skeletogenous septum in the spiny dogfish?

To divide the epaxial and hypaxial musculature (C) Signup and view all the answers

Which of the following best describes the location of the pectoral abductor muscle?

Dorsally, pulling the fin dorsally (C) Signup and view all the answers

What is the significance of the linea alba in the muscular system of the spiny dogfish?

It is a connective tissue that separate the left and right myomeres (B) Signup and view all the answers

Which sensory structures are primarily responsible for detecting electrical fields in the spiny dogfish?

Ampullae of Lorenzini (D) Signup and view all the answers

What is the function of the scapular process?

To attach to the coracoid bar located between the fins (A) Signup and view all the answers

Where are the external pharyngeal slits located in the spiny dogfish, and what divides them?

Divided by four interbranchial septa (B) Signup and view all the answers

What is the primary function of the rugae found within the stomach of a spiny dogfish?

To aid in the mechanical breakdown of food through muscular contractions. (C) Signup and view all the answers

Where is the spiracular valve located?

On the anterior wall of the spiracle (B) Signup and view all the answers

Which structure marks the separation between the stomach and the intestine in the spiny dogfish?

The pylorus (D) Signup and view all the answers

Which of these is true about the pancreas in the spiny dogfish?

It has two parts, a ventral lobe that adheres to the the duodenum and a narrow dorsal lobe. (C) Signup and view all the answers

What is the function of the labial fold in spiny dogfish?

To separate the mouth from the labial pocket (B) Signup and view all the answers

What is the role of the spleen in a spiny dogfish?

To produce and store blood cells as a lymphoid organ. (B) Signup and view all the answers

Which of the following best describes the path of water as it travels out of the pharynx in a spiny dogfish?

Through the internal gill slits, and over the gill lamellae. (D) Signup and view all the answers

In the digestive system of a spiny dogfish, what is the valvular intestine is positioned between?

The duodenum and the colon (D) Signup and view all the answers

Study Notes

Spiny Dogfish Shark (Squalus acanthias) Dissection: Part 1

Presented by Dr. Sarah Polekoff in BIO 415L
The dissection focuses on the Squalus acanthias species.

Dogfish Structures (Skeletal Elements)

Chondrocranium: Forms the head's skeletal structure.
Splanchnocranium: Supports the visceral structures.
Vertebral column: Extends from the chondrocranium to the tail.
Ribs: Supports the anterior and posterior dorsal fins, and caudal fin.
Pectoral girdle: Supports the pectoral fins.
Pelvic girdle: Supports the pelvic fins.

Dogfish Structures (External Structures)

Naris: Nose opening.
Eye: Visual organ.
Mouth: Opening for ingestion.
Labial pocket: Pocket-like structure around the mouth.
Spiracular valve: Opening to the spiracle.
Spiracle: Opening used for water intake near the eye.
External pharyngeal slits: Openings connected to the gill structures.
Interbranchial septum: Separates the pharyngeal slits.
Lateral line: Sensory system for detecting water pressure changes.
Anterior dorsal fin: Located on the back.
Posterior dorsal fin: Located on the back.
Caudal fin: Tail fin.
Pelvic fin: Located on the ventral surface.
Pectoral fin: Located on the ventral surface.
Claspers (male): Modified pelvic fins for mating.
Cloaca: Opening for excretion and reproduction.
Abdominal pore: Opening used for excretion.
Urinary papilla (male): Structure for excretion.
Urogenital papilla (female): Structure for excretion and reproduction.

Dogfish Structures (Muscular System)

Spiracle: Opening
Meckel's cartilage: Cartilage
Adductor mandibulae m.: Muscle
External pharyngeal slit: Opening
Scapular process: Part of the pectoral girdle
Myomere: Muscle segment
Myoseptum: Connective tissue separating myomeres.
Epaxial musculature: Dorsal muscle groups.
Horizontal skeletogenous septum: Septa separating muscle groups.
Hypaxial musculature: Ventral muscle groups.
Linea alba: Midline connective tissue.
Pectoral adductor m.: Muscle.
Ampullae of Lorenzini: Special sensory structures.

Dogfish Background

Class Chondrichthyes: Includes sharks, skates, rays, sawfishes, and holocephalimorphans.
Cartilaginous skeleton: Composed of cartilage instead of bone.
Mineralization: Perichondral and endochondral processes.
Teeth: Row of serrated, triangular and pointed teeth that are replaced frequently.
Placoid scales ('denticles'): Distinctive scales, akin to tiny teeth embedded in the skin.
Fins: Well-developed paired fins.
Spiracles: Openings that draw water over the gills.
Swim bladder (lacking): Oil-filled liver helps with buoyancy.
Evolutionary Positioning: Located in the Gnathostomata branch of the Vertebrata phylum.
Epaulette shark walking: Video links provided.

Other Relevant Information

Dissection preparation: Methods for preparing the dogfish for study. Diagrams provided.
Vertebral column and ribs: Structure and importance in the skeletal system. Diagrams provided.
Pectoral, pelvic, and caudal fins: Structure and location on the body. Diagrams provided.
Evolutionary biology: Position within the Vertebrata phylum and related groups. Diagrams provided. Specific external and internal structures relevant to this species' evolutionary context now included.
References: Citations for relevant texts and resources provided

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Description

Test your knowledge on the anatomy of spiny dogfish sharks with this quiz. Questions cover various components of their skeletal and muscular systems, as well as the functions of different structures like the labial cartilage and claspers. Perfect for students and enthusiasts of marine biology!